View
217
Download
0
Category
Preview:
Citation preview
Physics perspectives at JLab with 12 GeV beam
Marco Mirazita
INFN ndash Laboratori Nazionali di Frascati
XCVI Congresso Nazionale della Societarsquo Italiana di FisicaBologna 20-24 Settembre 2010
Newport News (VA) - USA
INFN is involved in the JLab activity
since 1991
A B C
Extractionelement
06 GeV Linac
45 MeV Injector
06 GeV Linac
5 Recirculation Arcs
Three Simultaneous Beams with Independently Variable Energy
and Intensity
Ee max 6 GeVImax 200 microADuty Factor 100 (CW beam)Pe 85
Jefferson Lab amp Cebaf
Hall A Two High Resolution (10-4) Spectrometers
Hall B The CEBAF Large Acceptance Spectrometer (CLAS)
Hall C A High Momentum and a Short Range Spectrometer
L[cm-2s-1] = 1039
High momentum final state and coincidence experiments with unstable particles
L[cm-2s-1] = 1039
High-precision electron-hadron coincidence exp
ELETTROLEDAISS+RM1+BA
L[cm-2s-1] = 1034
Electron and real photon exclusive reactions with multi-particle final states
AIACE LNF+GE
JLab physics program
quarksgluons
From nuclei to quarks a laboratory from ldquostrongrdquo to perturbative QCD
Start physics program in 1996 End physics program 6 GeV in 2012
heavynucleifew
body
quarksgluons
vacuum
CorrelationsHypernuclei
Eff NN (+ΛN) forcen-radii N ne Z
Hadrons in-medium
Baryon and meson excitation spectrumMissing resonances
ExoticsParton DFTMDGPD
3D imaging of the nucleon
PV e-scatteringStrange FF
6 GeV CEBAF
CHL-2
Upgrade magnets and power supplies
12 GeV CEBAF
Enhance equipment in existing halls
add Hall D (and beam line)
2008-2014 Construction (funded at 99 by DOE- cost 310 M$)
May 2012
6 GeV Accelerator Shutdown starts
May 2013Accelerator Commissioning starts
October 2013
Hall Commissioning starts
2013-2015
Pre-Ops (beam commissioning)
Imax = 90 microAEmax Hall ABC 109 GeVEmax Hall D 12 GeV
GlueExHRS
CLAS12
SHRS
Structure of the nucleonThe complex structure of the nucleon can be described through a large variety of functions
elastic FFcharge and current
distributionselastic scattering
transition FFinelastic scattering
GPDlongitudinal momentum distributions at a given
transverse pointexclusive reactions
PDFlongitudinal momentum distributions of partonsinclusive scattering
TMDlongitudinal and transverse momentum distributions of partonssemi-inclusive scattering
JLab main programdetermination of multi-dimensional parton distribution
functions in a large kinematics range
bull Discrepancy between Rosembluth and polarization methods is established charge and current dist are DIFFERENTbull The reason is not completely clear possible explanation can be TPE (CLAS measurement in 2010-11)bull Different models predicts different asymptotics will the ratio cross the zero
Nucleon FF
FF
( ) ( ) ( )[ ]2222
1QGQG
dd
EMMott
e
εττε
σσ+
+=
Ω
( )( ) 2
tan2
2
2eee
M
E
z
x
MEE
QGQG
PP ϑ+
minus=
FF experiments at JLab12
E12-07-109 Large acceptance proton Form Factor ratio measurements at 13 and 15 (GeVc)2 using recoil polarization method
E Cisbani co-spokesperson
E12-09-016 Measurement of the neutron electromagnetic Form Factor ratio GEnGMn at high Q2
E12-09-019 Precision measurement of the neutron magnetic Form Factor up to Q2=18(GeVc)2 by the rario mathod
HALL A
E12-07-104 Measurement of the neutron magnetic Form Factor at high Q2 using the ratio method on the deuterium
HALL B
High momentum proton detection requires upgrade of the existing spectrometer
The new SBS in Hall ARequirementsbull high luminosity (1038 cm-2 s-1 )bull small angle coveragebull ∆pp ~ 05 at 5-8 GeVc
SiliconDetectors
bull ∆θ ~ 2 mradbull relatively large acceptancebull flexibility
New SBS trackerbull large GEM tracking chambersbull silicon detectors to improve resolution
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Newport News (VA) - USA
INFN is involved in the JLab activity
since 1991
A B C
Extractionelement
06 GeV Linac
45 MeV Injector
06 GeV Linac
5 Recirculation Arcs
Three Simultaneous Beams with Independently Variable Energy
and Intensity
Ee max 6 GeVImax 200 microADuty Factor 100 (CW beam)Pe 85
Jefferson Lab amp Cebaf
Hall A Two High Resolution (10-4) Spectrometers
Hall B The CEBAF Large Acceptance Spectrometer (CLAS)
Hall C A High Momentum and a Short Range Spectrometer
L[cm-2s-1] = 1039
High momentum final state and coincidence experiments with unstable particles
L[cm-2s-1] = 1039
High-precision electron-hadron coincidence exp
ELETTROLEDAISS+RM1+BA
L[cm-2s-1] = 1034
Electron and real photon exclusive reactions with multi-particle final states
AIACE LNF+GE
JLab physics program
quarksgluons
From nuclei to quarks a laboratory from ldquostrongrdquo to perturbative QCD
Start physics program in 1996 End physics program 6 GeV in 2012
heavynucleifew
body
quarksgluons
vacuum
CorrelationsHypernuclei
Eff NN (+ΛN) forcen-radii N ne Z
Hadrons in-medium
Baryon and meson excitation spectrumMissing resonances
ExoticsParton DFTMDGPD
3D imaging of the nucleon
PV e-scatteringStrange FF
6 GeV CEBAF
CHL-2
Upgrade magnets and power supplies
12 GeV CEBAF
Enhance equipment in existing halls
add Hall D (and beam line)
2008-2014 Construction (funded at 99 by DOE- cost 310 M$)
May 2012
6 GeV Accelerator Shutdown starts
May 2013Accelerator Commissioning starts
October 2013
Hall Commissioning starts
2013-2015
Pre-Ops (beam commissioning)
Imax = 90 microAEmax Hall ABC 109 GeVEmax Hall D 12 GeV
GlueExHRS
CLAS12
SHRS
Structure of the nucleonThe complex structure of the nucleon can be described through a large variety of functions
elastic FFcharge and current
distributionselastic scattering
transition FFinelastic scattering
GPDlongitudinal momentum distributions at a given
transverse pointexclusive reactions
PDFlongitudinal momentum distributions of partonsinclusive scattering
TMDlongitudinal and transverse momentum distributions of partonssemi-inclusive scattering
JLab main programdetermination of multi-dimensional parton distribution
functions in a large kinematics range
bull Discrepancy between Rosembluth and polarization methods is established charge and current dist are DIFFERENTbull The reason is not completely clear possible explanation can be TPE (CLAS measurement in 2010-11)bull Different models predicts different asymptotics will the ratio cross the zero
Nucleon FF
FF
( ) ( ) ( )[ ]2222
1QGQG
dd
EMMott
e
εττε
σσ+
+=
Ω
( )( ) 2
tan2
2
2eee
M
E
z
x
MEE
QGQG
PP ϑ+
minus=
FF experiments at JLab12
E12-07-109 Large acceptance proton Form Factor ratio measurements at 13 and 15 (GeVc)2 using recoil polarization method
E Cisbani co-spokesperson
E12-09-016 Measurement of the neutron electromagnetic Form Factor ratio GEnGMn at high Q2
E12-09-019 Precision measurement of the neutron magnetic Form Factor up to Q2=18(GeVc)2 by the rario mathod
HALL A
E12-07-104 Measurement of the neutron magnetic Form Factor at high Q2 using the ratio method on the deuterium
HALL B
High momentum proton detection requires upgrade of the existing spectrometer
The new SBS in Hall ARequirementsbull high luminosity (1038 cm-2 s-1 )bull small angle coveragebull ∆pp ~ 05 at 5-8 GeVc
SiliconDetectors
bull ∆θ ~ 2 mradbull relatively large acceptancebull flexibility
New SBS trackerbull large GEM tracking chambersbull silicon detectors to improve resolution
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Hall A Two High Resolution (10-4) Spectrometers
Hall B The CEBAF Large Acceptance Spectrometer (CLAS)
Hall C A High Momentum and a Short Range Spectrometer
L[cm-2s-1] = 1039
High momentum final state and coincidence experiments with unstable particles
L[cm-2s-1] = 1039
High-precision electron-hadron coincidence exp
ELETTROLEDAISS+RM1+BA
L[cm-2s-1] = 1034
Electron and real photon exclusive reactions with multi-particle final states
AIACE LNF+GE
JLab physics program
quarksgluons
From nuclei to quarks a laboratory from ldquostrongrdquo to perturbative QCD
Start physics program in 1996 End physics program 6 GeV in 2012
heavynucleifew
body
quarksgluons
vacuum
CorrelationsHypernuclei
Eff NN (+ΛN) forcen-radii N ne Z
Hadrons in-medium
Baryon and meson excitation spectrumMissing resonances
ExoticsParton DFTMDGPD
3D imaging of the nucleon
PV e-scatteringStrange FF
6 GeV CEBAF
CHL-2
Upgrade magnets and power supplies
12 GeV CEBAF
Enhance equipment in existing halls
add Hall D (and beam line)
2008-2014 Construction (funded at 99 by DOE- cost 310 M$)
May 2012
6 GeV Accelerator Shutdown starts
May 2013Accelerator Commissioning starts
October 2013
Hall Commissioning starts
2013-2015
Pre-Ops (beam commissioning)
Imax = 90 microAEmax Hall ABC 109 GeVEmax Hall D 12 GeV
GlueExHRS
CLAS12
SHRS
Structure of the nucleonThe complex structure of the nucleon can be described through a large variety of functions
elastic FFcharge and current
distributionselastic scattering
transition FFinelastic scattering
GPDlongitudinal momentum distributions at a given
transverse pointexclusive reactions
PDFlongitudinal momentum distributions of partonsinclusive scattering
TMDlongitudinal and transverse momentum distributions of partonssemi-inclusive scattering
JLab main programdetermination of multi-dimensional parton distribution
functions in a large kinematics range
bull Discrepancy between Rosembluth and polarization methods is established charge and current dist are DIFFERENTbull The reason is not completely clear possible explanation can be TPE (CLAS measurement in 2010-11)bull Different models predicts different asymptotics will the ratio cross the zero
Nucleon FF
FF
( ) ( ) ( )[ ]2222
1QGQG
dd
EMMott
e
εττε
σσ+
+=
Ω
( )( ) 2
tan2
2
2eee
M
E
z
x
MEE
QGQG
PP ϑ+
minus=
FF experiments at JLab12
E12-07-109 Large acceptance proton Form Factor ratio measurements at 13 and 15 (GeVc)2 using recoil polarization method
E Cisbani co-spokesperson
E12-09-016 Measurement of the neutron electromagnetic Form Factor ratio GEnGMn at high Q2
E12-09-019 Precision measurement of the neutron magnetic Form Factor up to Q2=18(GeVc)2 by the rario mathod
HALL A
E12-07-104 Measurement of the neutron magnetic Form Factor at high Q2 using the ratio method on the deuterium
HALL B
High momentum proton detection requires upgrade of the existing spectrometer
The new SBS in Hall ARequirementsbull high luminosity (1038 cm-2 s-1 )bull small angle coveragebull ∆pp ~ 05 at 5-8 GeVc
SiliconDetectors
bull ∆θ ~ 2 mradbull relatively large acceptancebull flexibility
New SBS trackerbull large GEM tracking chambersbull silicon detectors to improve resolution
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
JLab physics program
quarksgluons
From nuclei to quarks a laboratory from ldquostrongrdquo to perturbative QCD
Start physics program in 1996 End physics program 6 GeV in 2012
heavynucleifew
body
quarksgluons
vacuum
CorrelationsHypernuclei
Eff NN (+ΛN) forcen-radii N ne Z
Hadrons in-medium
Baryon and meson excitation spectrumMissing resonances
ExoticsParton DFTMDGPD
3D imaging of the nucleon
PV e-scatteringStrange FF
6 GeV CEBAF
CHL-2
Upgrade magnets and power supplies
12 GeV CEBAF
Enhance equipment in existing halls
add Hall D (and beam line)
2008-2014 Construction (funded at 99 by DOE- cost 310 M$)
May 2012
6 GeV Accelerator Shutdown starts
May 2013Accelerator Commissioning starts
October 2013
Hall Commissioning starts
2013-2015
Pre-Ops (beam commissioning)
Imax = 90 microAEmax Hall ABC 109 GeVEmax Hall D 12 GeV
GlueExHRS
CLAS12
SHRS
Structure of the nucleonThe complex structure of the nucleon can be described through a large variety of functions
elastic FFcharge and current
distributionselastic scattering
transition FFinelastic scattering
GPDlongitudinal momentum distributions at a given
transverse pointexclusive reactions
PDFlongitudinal momentum distributions of partonsinclusive scattering
TMDlongitudinal and transverse momentum distributions of partonssemi-inclusive scattering
JLab main programdetermination of multi-dimensional parton distribution
functions in a large kinematics range
bull Discrepancy between Rosembluth and polarization methods is established charge and current dist are DIFFERENTbull The reason is not completely clear possible explanation can be TPE (CLAS measurement in 2010-11)bull Different models predicts different asymptotics will the ratio cross the zero
Nucleon FF
FF
( ) ( ) ( )[ ]2222
1QGQG
dd
EMMott
e
εττε
σσ+
+=
Ω
( )( ) 2
tan2
2
2eee
M
E
z
x
MEE
QGQG
PP ϑ+
minus=
FF experiments at JLab12
E12-07-109 Large acceptance proton Form Factor ratio measurements at 13 and 15 (GeVc)2 using recoil polarization method
E Cisbani co-spokesperson
E12-09-016 Measurement of the neutron electromagnetic Form Factor ratio GEnGMn at high Q2
E12-09-019 Precision measurement of the neutron magnetic Form Factor up to Q2=18(GeVc)2 by the rario mathod
HALL A
E12-07-104 Measurement of the neutron magnetic Form Factor at high Q2 using the ratio method on the deuterium
HALL B
High momentum proton detection requires upgrade of the existing spectrometer
The new SBS in Hall ARequirementsbull high luminosity (1038 cm-2 s-1 )bull small angle coveragebull ∆pp ~ 05 at 5-8 GeVc
SiliconDetectors
bull ∆θ ~ 2 mradbull relatively large acceptancebull flexibility
New SBS trackerbull large GEM tracking chambersbull silicon detectors to improve resolution
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
6 GeV CEBAF
CHL-2
Upgrade magnets and power supplies
12 GeV CEBAF
Enhance equipment in existing halls
add Hall D (and beam line)
2008-2014 Construction (funded at 99 by DOE- cost 310 M$)
May 2012
6 GeV Accelerator Shutdown starts
May 2013Accelerator Commissioning starts
October 2013
Hall Commissioning starts
2013-2015
Pre-Ops (beam commissioning)
Imax = 90 microAEmax Hall ABC 109 GeVEmax Hall D 12 GeV
GlueExHRS
CLAS12
SHRS
Structure of the nucleonThe complex structure of the nucleon can be described through a large variety of functions
elastic FFcharge and current
distributionselastic scattering
transition FFinelastic scattering
GPDlongitudinal momentum distributions at a given
transverse pointexclusive reactions
PDFlongitudinal momentum distributions of partonsinclusive scattering
TMDlongitudinal and transverse momentum distributions of partonssemi-inclusive scattering
JLab main programdetermination of multi-dimensional parton distribution
functions in a large kinematics range
bull Discrepancy between Rosembluth and polarization methods is established charge and current dist are DIFFERENTbull The reason is not completely clear possible explanation can be TPE (CLAS measurement in 2010-11)bull Different models predicts different asymptotics will the ratio cross the zero
Nucleon FF
FF
( ) ( ) ( )[ ]2222
1QGQG
dd
EMMott
e
εττε
σσ+
+=
Ω
( )( ) 2
tan2
2
2eee
M
E
z
x
MEE
QGQG
PP ϑ+
minus=
FF experiments at JLab12
E12-07-109 Large acceptance proton Form Factor ratio measurements at 13 and 15 (GeVc)2 using recoil polarization method
E Cisbani co-spokesperson
E12-09-016 Measurement of the neutron electromagnetic Form Factor ratio GEnGMn at high Q2
E12-09-019 Precision measurement of the neutron magnetic Form Factor up to Q2=18(GeVc)2 by the rario mathod
HALL A
E12-07-104 Measurement of the neutron magnetic Form Factor at high Q2 using the ratio method on the deuterium
HALL B
High momentum proton detection requires upgrade of the existing spectrometer
The new SBS in Hall ARequirementsbull high luminosity (1038 cm-2 s-1 )bull small angle coveragebull ∆pp ~ 05 at 5-8 GeVc
SiliconDetectors
bull ∆θ ~ 2 mradbull relatively large acceptancebull flexibility
New SBS trackerbull large GEM tracking chambersbull silicon detectors to improve resolution
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Structure of the nucleonThe complex structure of the nucleon can be described through a large variety of functions
elastic FFcharge and current
distributionselastic scattering
transition FFinelastic scattering
GPDlongitudinal momentum distributions at a given
transverse pointexclusive reactions
PDFlongitudinal momentum distributions of partonsinclusive scattering
TMDlongitudinal and transverse momentum distributions of partonssemi-inclusive scattering
JLab main programdetermination of multi-dimensional parton distribution
functions in a large kinematics range
bull Discrepancy between Rosembluth and polarization methods is established charge and current dist are DIFFERENTbull The reason is not completely clear possible explanation can be TPE (CLAS measurement in 2010-11)bull Different models predicts different asymptotics will the ratio cross the zero
Nucleon FF
FF
( ) ( ) ( )[ ]2222
1QGQG
dd
EMMott
e
εττε
σσ+
+=
Ω
( )( ) 2
tan2
2
2eee
M
E
z
x
MEE
QGQG
PP ϑ+
minus=
FF experiments at JLab12
E12-07-109 Large acceptance proton Form Factor ratio measurements at 13 and 15 (GeVc)2 using recoil polarization method
E Cisbani co-spokesperson
E12-09-016 Measurement of the neutron electromagnetic Form Factor ratio GEnGMn at high Q2
E12-09-019 Precision measurement of the neutron magnetic Form Factor up to Q2=18(GeVc)2 by the rario mathod
HALL A
E12-07-104 Measurement of the neutron magnetic Form Factor at high Q2 using the ratio method on the deuterium
HALL B
High momentum proton detection requires upgrade of the existing spectrometer
The new SBS in Hall ARequirementsbull high luminosity (1038 cm-2 s-1 )bull small angle coveragebull ∆pp ~ 05 at 5-8 GeVc
SiliconDetectors
bull ∆θ ~ 2 mradbull relatively large acceptancebull flexibility
New SBS trackerbull large GEM tracking chambersbull silicon detectors to improve resolution
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
bull Discrepancy between Rosembluth and polarization methods is established charge and current dist are DIFFERENTbull The reason is not completely clear possible explanation can be TPE (CLAS measurement in 2010-11)bull Different models predicts different asymptotics will the ratio cross the zero
Nucleon FF
FF
( ) ( ) ( )[ ]2222
1QGQG
dd
EMMott
e
εττε
σσ+
+=
Ω
( )( ) 2
tan2
2
2eee
M
E
z
x
MEE
QGQG
PP ϑ+
minus=
FF experiments at JLab12
E12-07-109 Large acceptance proton Form Factor ratio measurements at 13 and 15 (GeVc)2 using recoil polarization method
E Cisbani co-spokesperson
E12-09-016 Measurement of the neutron electromagnetic Form Factor ratio GEnGMn at high Q2
E12-09-019 Precision measurement of the neutron magnetic Form Factor up to Q2=18(GeVc)2 by the rario mathod
HALL A
E12-07-104 Measurement of the neutron magnetic Form Factor at high Q2 using the ratio method on the deuterium
HALL B
High momentum proton detection requires upgrade of the existing spectrometer
The new SBS in Hall ARequirementsbull high luminosity (1038 cm-2 s-1 )bull small angle coveragebull ∆pp ~ 05 at 5-8 GeVc
SiliconDetectors
bull ∆θ ~ 2 mradbull relatively large acceptancebull flexibility
New SBS trackerbull large GEM tracking chambersbull silicon detectors to improve resolution
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
FF experiments at JLab12
E12-07-109 Large acceptance proton Form Factor ratio measurements at 13 and 15 (GeVc)2 using recoil polarization method
E Cisbani co-spokesperson
E12-09-016 Measurement of the neutron electromagnetic Form Factor ratio GEnGMn at high Q2
E12-09-019 Precision measurement of the neutron magnetic Form Factor up to Q2=18(GeVc)2 by the rario mathod
HALL A
E12-07-104 Measurement of the neutron magnetic Form Factor at high Q2 using the ratio method on the deuterium
HALL B
High momentum proton detection requires upgrade of the existing spectrometer
The new SBS in Hall ARequirementsbull high luminosity (1038 cm-2 s-1 )bull small angle coveragebull ∆pp ~ 05 at 5-8 GeVc
SiliconDetectors
bull ∆θ ~ 2 mradbull relatively large acceptancebull flexibility
New SBS trackerbull large GEM tracking chambersbull silicon detectors to improve resolution
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
The new SBS in Hall ARequirementsbull high luminosity (1038 cm-2 s-1 )bull small angle coveragebull ∆pp ~ 05 at 5-8 GeVc
SiliconDetectors
bull ∆θ ~ 2 mradbull relatively large acceptancebull flexibility
New SBS trackerbull large GEM tracking chambersbull silicon detectors to improve resolution
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Transverse degrees of freedom are importantNucleon spin decomposition
∆Σ = ∆uV + ∆dV
12
=12
∆Σ
asymp 03
The nucleon parton model
+∆G
+∆qS
small
+Lq
kperp
could be large
In the collinear approximation
P Pxp
=
q)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions8 DF at leading twist
)(1 Tpxf
Inclusive DIS Dist Functions
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
PT
SIDIS Observables
Beam helicityTarget polarization
U unpolarized
L longpolarized
T transpolarized
σ = σUU + ST σUT sin(φ ndash φS) + λ ST σLT cos(φ ndash φS) +
1 high intensity beam with high polarization2 polarized targets3 high acceptance for the hadron (charged or neutrals)
Semi-Incusive Deep Inelastic Scatteringe N rarr ersquo h X
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
PDF and TMD measurements at 6 GeVMeasurements of PDFampTMD already play a big role in the 6 GeV program
bull With longitudinally polarized beam andor target- beam polarization ~70 - target polarization ~75 (H) ~30 (D)
)( 21 Qxg
bull photon run with HD-ice Mar-May 2011bull test run with e- May 2011bull physics run with e- ()Expected luminosity L~ 5 1033
Transversely polarized target HD-iceSeveral advantagesbull high H (95) and D (70) polarization with high dilution factorbull wider acceptanceVery complicated targetbull long production cyclebull need to optimize several parametersbull can remain polarized under a high intensity electron beam
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
SIDIS experiments at JLab12PR-09-018 Measurement of the Semi-Inclusive p and K electro-production in DIS regime from transversely polarized 3He target E Cisbani co-spokesperson
HALL A
New SBS
E12-09-007 Studies of partonic distributions using semi-inclusive production of Kaons M Mirazita co-spokesperson
E12-09-008 Studies of the Boer-Mulders asymmetry in Kaonelectroproduction with hydrogen and deuterium targets
M Contalbrigo co-spokesperson
E12-09-009 Studies of spin-orbit correlations in Kaon electroproduction in DIS with longitudinally polarized hydrogen and deuterium targets
E Cisbani P Rossi co-spokesperson
E12-06-112 Probing the Protonrsquos Quark Dinamics in Semi-Inclusive PionProduction at 12 GeV
E12-07-107 Studies Studies of Spin-Orbit Correlations with Longitudinally Polarized Target (Pion) P Rossi co-spokesperson
HALL B
Kaon measurements are a large part of the TMD program in Hall-B
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
PID in CLAS12
Scintillator Counters (TOF) with timing resolution of 80 and 150
ps for charged hadron ID
Electromagnetic Calorimeter lead and scintillators for eπseparation and γn detection
Low Threshold Cerenkov Counter (LTCC) for (pK)π separation
High Threshold Cerenkov Counter (HTCC) for eπ separation
GeVc 1 2 3 4 5 6 7 8 9 10
πK
πp
Kp
TOF
TOF
LTCCHTCC
HTCC
LTCC
TOF
LTCC
bull Need good Kaon ID in the 2-8 GeVc
momentum range
bull πK rejection factor of 11000 for SIDIS
experiments
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
The RICH project for CLAS12 Charged particle
Radiator
Proximity gap
Photon detector
Aerogel mandatory to separate hadrons in the momentum range 2-8 GeVc
Collection of the visible Cherenkov lightrArr larger Npe
Small pad size (lt 1cm)rArr better resolution
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Workshop
ldquoProbing Strangeness in Hard Processesrdquo
Laboratori Nazionali diFrascati
October 18-21 2010
httpwwwlnfinfnitconferencepshp2010indexhtml
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Generalized Parton Distributions
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξFor the unpolarized or longitudinal polarized case there are 4 GPDs
After Fourier transformlongitudinal momentum distributions of quark at a given transverse point in the nucleon
rArr 3D imaging of the nucleon
GPDs are not directly accessiblerArr - need deconvolution
- model dependent
GPDs are the generalization of partondistribution functions when one allows- momentum transfer to the nucleon- longitudinal momentum transfer to the quark
DIS cross section
They represent interference of amplitudes rArr NO probabilistic interpretation
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
GPDs from theory to experiments
Can be measured in exclusive electroproductionexperiments
Deeply Virtual Compton Scattering (DVCS)
Different final state andor polarizations selects different GPDs
bull DVCS (γ) H E H E
bull VM (ρ ω φ) H E
bull PS mesons (π η) H E ~
~ ~
~
Re[F1H]
Im[F1H]
Im[F1H]~Im[F2H- F1E]
~Im[F2H- ξF1E]~
~Re[HHE]~~Re[HHE]~
DVCS observables
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Measurement of GPD E
CLAS12 Central Detector
Neutron Detector
nDVCS by detecting the scattered neutron in the central detectorLimitation bull High magnetic field (2-5 Tesla)bull Limited space (mainly for the read-out)
Geometry of the detector is defined electronic readout is under study
- SiPM- MWPC- readout from the backward side only
ΑLU(sinφ) prop [ ] H1FmimageDVCS on the proton γ pepe rarr
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξJi sum-rule
DVCS on the neutron )( pnede γrarr [ ] E2 Fmimage++
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
14 GeV - 30 GeV(5 GeV lt Eg lt9 GeV)
Meson map
(qq angular momentum)-L = 0 1 2 3 4 5
Exotic nonets Hybrid mesons andglueballs mass range
Lattice-QCD predictions for the
lowest hybrid states
0++ 16 GeV1-+ 19 GeV
Meson Spectroscopybeyond the quark model
Experimental signature for the presence of gluonic dof in the spectrum of mesonic states
mesons with exotic quantum numbers (not compatible with quark-model)
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Meson Spectroscopy with real photonsMeson (and baryon) spectroscopy with real photons is the main goal of the Hall-D- exotic JPC more likely produced by J=1 probe- production rate comparable to regular mesons
This program can be pursued in a complementary way in Hall-B- high luminosity- ldquotaggingrdquo of the photon - linear polarization to simplify Partial Wave Analysis
Quasi-real electroproduction at low Q2 (lt10-1 GeV2)- detect scattered electron at small angle (2-5 deg)- photon energy 7 lt E lt 105 GeV- linear polarization ~ 65 ndash 20- photon flux ~ 5 107s
calorimeter + tracking + veto
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Conclusions
Institutions Bari Catania Ferrara Genova Laboratori Nazionali di Frascati ISSRoma I Roma II
Researchers 47 (~33 FTE)Technicians 31 (~13 FTE)
Research activity in Hall A amp Hall B Main fields of investigations TMDs GPDs Nucleon Form Factors Meson Spectroscopy
Hardware contribution to the 12 GeV upgradeNeutron Detector for the nDVCS measurement (Hall B)
SBS Front tracker for the proton form factor measurement at high Q2 (Hall A)RICH detector for TMDs measurements (Hall B)Forward tagger for meson spectroscopy investigation (Hall B)
JLab12 is the new Collaboration born in 2009 for the Italian activity at Jefferson Lab
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
backup slides
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
FF measurement at 12 GeV
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
tmd
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
The nucleon parton modelIn the collinear approximation
P Pxp
=
q DIS distribution functions
)( )( )( xhxgxf 111
Parton transverse momentum
P
TpPxp +=
qTp
more complex dist functions
)( )( )( TTT pxhpxgpxf 111
A wealth of new PDFTRANSVERSE MOMENTUM DEPENDENT DF (TMD)
bull full description of quarks in the nucleonbull only f1 g1 and h1 survive pT integration
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
DF
FF
Factorization in SIDIS process
DISTRIBUTION
FRAGMENTATION
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
tmd misure
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Study of high xB domain requires high luminosity
12 GeV Kinematical coverage
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
π0 multiplicity
eprarrersquoπ0X
In the valence region mult iplicitysimFFAgreement with FF extraction from world data
DSS (Q2=25GeV2)
DSS (Q2=25GeV2)
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Pion Beam Spin Asymmetry (BSA)
σ prop A1FUU(1) + A2 FUU
(2) cos(2φ) + λ (MQ) B3 FLU sin(φ)
Higher twist effecte p rarrersquoπ Xunpolarized target polarized beam
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
11)1( DfFUU otimesprop
perpperp otimesprop11
)2( HhFUUSMALL
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
π0 BSA - Results
Drop with PT below 1 GeVc
Asymmetry in agreement with Hermes data
φsinLUA
φsinLUA
φsinLUA
From power counting FLU sim1PTBacchetta et al arXiv08090227[hep-ph]
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Pion BSA
Comparable BSA for π0 and π+
Small Collins type contributions for π+
otimes+otimes
otimesminusotimesprop
perpperp
perpperp
zEhHxe
zG
fMMDxg
MM
Fh
hLU
1
1
1
1
Main Contribution
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Pion SSA with longitudinal target
e p rarrersquoπ X
σ prop σUU+ SL [A4 FUL(1) sin(2φ) + (MQ) B3 FUL
(2) sin(φ)] +λSLA3FLLleading-twist higher-twist
unpolarized beampolarized beam
otimes+otimes
otimes+otimesprop
perpperp
perpperp
zHhHxh
zG
gMMDxf
MM
F
LL
hL
hUL ~
1
1)2(
1
1
perpperp otimesprop11
)1( HhF LUL
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Target SSA for pions
p1sinφ+p2sin2φ eprarrersquoπXCLAS PRELIMINARY
p1= 0059plusmn0010p2=-0041plusmn0010
p1=-0042plusmn0015p2=-0052plusmn0016
p1=0082plusmn0018p2=0012plusmn0019
AUL(φ)
π+ π- π0
bullcomparable sinφresults for π+ and π0bullnon-negligiblehigher twists
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Kotzinian-Mulders asymmetry
bull Non-zero negative asymmetry for charged pionsbull Small asymmetry for π0
curves χQSM from Efremov et al
60 days of CLAS at 6 GeVL=151034cm-2s-1
data taking ended in June
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
TMDs with Transverse Target
σ prop σUU + |Sperp| [A5FUT(1) sin(φminusφS) + A7 FUT
(2) sin(φ+φS)+ A8 FUT
(3) sin(3φminusφS) ] + ht
Leading twist
e p rarrersquoπ Xunpolarized beam transv polarized beam
perpperp otimesprop11
)3( HhF TUT
11)1( DfF TUT otimesprop perp
perpotimesprop11
)2( HhFUT
Sivers TMD
transversityTMD
Collins FF
pretzelosityTMD
Collins FF
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Sivers effect sin(φ-φS)
( )STUT DfF φφ minusotimesprop perp sin11)1( direct extraction of Sivers DF
bull Non-zero effectbull Need data at large x
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
High beam polarization rArr access to ALT
curves from Yuan EfremovCollins
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Collins effect sin(φ+φS)
bull π+ and π- have opposite signbull small (zero) asymmetry for π0 Collins FF is zero for π0
30 days of CLAS at 6 GeV in 2011PT=75 L=51033cm-2s-1
curves fromAnselmino
( )SUT HhF φφ +otimesprop perp sin11
)2( access to transversity
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Boer-Mulders asymmetry at CLAS12
CLAS12
Non-perturbative TMD Perturbative region
PT-dependence of BM asymmetry allows studies of transition from non-perturbativeto perturbative description (Unified theory by Ji et al)
1500h 11 GeV with 1035sec-1cm-2)
unpolarized beam and target
( )
prop perpperp φ2cos11
11
HhDf
FUU
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Sivers effect pion amp kaon at CLAS12
S Arnold et al arXiv08052137
M Anselmino et al arXiv08052677
( )STUT DfF φφ minusotimesprop perp sin11)1(
unpolarized beam transverse target
2000 hours11GeV
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Pretzelosity at CLAS12
unpolarized beam transv target prophigher twist term
Exciting relation(in bag amp spectator model)
g1q (x)minus h1
q (x)= h1Tq(1)(x)
Avakian et al PRD78114024
2000 hours11GeV
non spherical shape of the nucleon
u quark
kperp=0
kperp=20 GeV
Sperp
B Pasquini et al arXiv08062298
kperp
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Hall A
bull Beam 6 GeV 15 microA (target limit)bull Neutron Target
High pressure polarized 3He 50 mgcm2 Pol ~ 60bull Hadron Detection HRS Left Ph = 24 GeVc πK IDbull Kinematic Region
ltQ2gt = 22 GeV2 x = 013divide04 z ~ 05
e-
π+-
1 month data takingstatistical errors comparable to
HERMES(3 years)COMPASS(2 years)
bullAnalysis underway
TMDs on a transversely pol neutron in HALL A
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
rich
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
RICH ActivityBA+CT+GE+RM1+LNF+FE+ISS
bull Monte Carlo simulation with GEANT3 in progressradiator C6F14AerogelDetected Cherenkov light visibleGeometry parameters pad size gap lenght radiator thickness
bull Preliminary results 5σ π-K separation 8 GeVc reachable (3 cm AEROGEL 06 cm pad size 100 cm gap)
bull Monte Carlo simulation with GEANT4 in progress
Electronic readout requests- visible light detection- compact- single pe detection- small pad size
bull Multi-anode PMTsbull SiPMs
MilestonesDOE review of the RICH project by the end of the year =gt ldquobaselinerdquo CLAS12 equipment
full funding by DOE for 6 sectors PRIN for a prototype Bari+Catania+ Genova+Roma I + Frascati+FerraraTest of a prototype in marchapril 2011
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
gpd
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
GPD properties
dxminus1
1int H (xξ t) = F1( t) dx
minus1
1int E(xξ t) = F2( t) The form factor limit
The forward limit
( )xqtxHt
=rarr
)(0
lim ξξ
( )xqtxHt
∆=rarr
)(~
0lim ξ
ξThe Ji sum rule
( ) ( )[ ]00 =+==+∆Σ= int txEtxHxdxLJ qqq 1
-1
ξξ
bull GPDs are not directly accessible rArr - need deconvolution- model dependent
bull multidimensional analysis of cross section
Constraints from other measurements
For the unpolarized or longitudinal polarized case there are 4 GPDs
( ) ( ) ( ) ( )txEtxEtxHtxH ~~ ξξξξ
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
DVCS Polarized Beam Asymmetry
e p epγ
A =∆σ2σ
σ + minus σ minus
σ + + σ minus =
∆σLU~sinφF1H+hellipdφ
Extract H(ξt)
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Projected results Spatial Image
Projected extraction of GPD H at x = ξ
22509 53Volker Burkert CLAS12 Workshop Genoa
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
cnd
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
Clean exclusive reconstruction of the DVCS process
requires detection and measurement of all three final state particles
The DVCS recoil neutrons
en e n γrarr
Scattered electron and photon are typically produced at low forward angles (into forward detector of CLAS 12)
Over 80 of neutrons recoil at θlab gt 40deg with peak momentum at ~ 04 GeVc
Requires central neutron detector sensitive to 02 lt pn lt 12 GeVc
larr Simulation at Ee= 11 GeV (Grenoble A El Alaoui)
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
CND Timing resolutionn ID by time-of-flight measurementrequired resolution ~120 ps
pn = 04 GeVcpn = 06 GeVcpn = 1 GeVcEγ = 1 GeV
β distributions
Test of SiPM timing resolution with Sr90 sourcebull one single SiPM
σt ~ 300 ps if npegt50
bull measurement with a 4x4 matrixbull only 4 channels instrumentedbull verified expected scaling with the number of channels
Test of SiPM with cosmic rays underway
GE-LNF
spectroscopy
spectroscopy
Recommended