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X. Dong / LBNL1
Aug. 2nd, 2007, DOE TOF Review, BNL
Physics objectives, Performance Requirements and Installation Plan
Xin DongLawrence Berkeley National Lab
Outline
➢ Physics Goals
➢ Performance Requirements for TOF
➢ Achievable Physics Objectives with TOF
➢ Near term BUR and TOF installation Plan
2X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Long Term: medium thermal/chiral properties
U+U collisions jet fragments tagged by a hard direct
photon, a heavy flavor heavy quarkonium species Thermometers: dilepton, photon fundamental QCD symmetries
STAR Physics Goals
STAR white paper Nucl. Phys. A 757 (2005) 102
Near Term: thermalization evidence, phase boundary
v2 scaling for coalescence
jet quenching as parton energy loss energy scan to search for critical point heavy flavor yields and flow: color
screening and partonic collectivity
RHIC heavy ion programTo search QGP and measure its properties- a (locally) thermally equilibrated, deconfiedstate of matter
A hot, dense matter with partonic collectivity has been created.
3X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Hadron PID
Lepton PID
v2 scaling for coalescence
jet quenching: parton energy loss
energy scan to search for critical
point
heavy flavor yields and flow: color
screening and partonic collectivity
U+U collisions
jet fragments tagged by a hard
direct photon, a heavy flavor
heavy quarkonium species
Thermometers: dilepton, photon
fundamental QCD symmetries
➢ PID spectra & v2
➢ PID correlations &
fluctuations
➢ Lepton spectra & v2
➢ Di-lepton pair
How to achieve
4X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Performance requirements and Achievements
Requirements:
● Good timing resolution: < 100 ps in Au+Au collisions
● Small occupancy per channel: < 10-15%
● Rate capability: 200 Hz/cm2
● High efficiency: > 90%
Achievements from the prototypes:
• 85 ps timing resolution achieved in Au+Au.
• 3 cm x 6 cm, 120x32x6 read out, large granularity
• Rate capability: 500 Hz/cm2 (test beam, CERN)
• High efficiency: > 95%
Electron PID to low momentum~0.2 – intermediate p
T
Muon PID at low momentum~0.2 GeV/c
5X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
~80 (70)~82 (72)~20HF
~92 (73)~105 (92)~ 50200GeV Cu+Cu (ToT)Run V2005 ~94 (94)~125 (125)~ 8262GeV Cu+Cu (ToT)
~82 (71)~86 (74)~27FF/RFF
~86~96~40FF/RFF,
w/o E pVPD200GeV Au+Au
~89~105~5562GeV Au+Au
Run IV2004
~80~160~140200GeV p+p
~85~120~85200GeV d+AuRun III2003
TOFr (stop)
TOFr (overall)
pVPD
Time Resolution (ps)
Operation conditions
Performance of TOF prototypes
6X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
PID from TOFHadron PID
|1/β-1|<0.03
Electron PID
(Low mom) Muon PID
1) Hadrons: up to ~3-5 GeV/c with rdE/dx, reach ~12 GeV/c2) Electrons: ~0.2 - ~5GeV/c (or more)3) Muons: ~0.2 GeV/c
muon
7X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
➢ PID spectra & v2
➢ Freeze-out characteristics
➢ Hadronization scheme
➢ Energy loss
➢ PID correlations & fluctuations
➢ Lepton spectra & v2
➢ Di-lepton pair
Achievable Physics Topics with TOF
8X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
pT (GeV/c)0
~2 ~6
Jet quenchingpQCD at work, high density matter
Hydro at workstrong interactionscollectivity
NCQ scalingpartonic d.o.f
PID Spectra & v2
Freeze-out Hadronization scheme Jet energy loss
1) /K/p with limited pT reach
2) multi-stange particles and resonances have big statistics uncertainties
Freeze-out characteristics of multi-strange particles and resonances?Thermal/hard components in coalescence? Or scaling variables?
Before TOF
What will TOF do
1) more precision ,K,p measurements with full TOF2) much more efficient measurements for multi-strange baryons3) Add in resonance data points with help of TOF4) Calibrate (r)dE/dx to reach momentum beyond 10 GeV/c
9X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
(r)dE/dx calibration by TOF
Log10
(p)
Log 10
(dE
/dx )
TOF covers 0.2<pT<~5 GeV/c
dE/dx at relativistic (rdEdx) rise PID
covers ~3< pT< ~ 10 GeV/c
dE/dx calibration matters!!!
10X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
How TOF helps PID spectra & v2
STAR, PRL 97 (2006) 152301 STAR, PRC 75 (2007) 054906
Identified stable hadrons spectra and v2 measurements throughout whole p
T
Better yield, <pT> constrain
Baryon/meson difference in intermediate pT
B/M enhancement in Au+Au collisions Cronin Effect in d+Au collisionsSignificant improvement on multi-strange baryon and resonance measurements
pT (GeV/c)
v2
200 GeV
62 GeV
11X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
How TOF helps resonance reconstruction
Au+Au 200 GeV DataWith TPC only, the background shape of resonance invariant mass distributions is complicated mainly due to particle mis-identification.
K*
phi
From Data From simulation (proposal)
Yichun XuHaibin Zhang
12X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
➢ PID spectra & v2
➢ PID correlations & fluctuations
➢ medium chemical/kinetic properties
➢ Un-statistical fluctuations
➢ Lepton spectra & v2
➢ Di-lepton pair
Achievable Physics Topics with TOF
13X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Jet associated particle correlationsLeadinghadrons
Medium
STAR PRL 95 (2005) 152301
away
near
Medium
mach cone
Au+Au central
Jason Ulery
• Away-side spectra approaching the bulk
• Chemically and/or thermally?
• Need PID 1<pT<4 GeV/c
3-Particle Correlations:
Conical emission • mach cone• Cerenkov radiation
PID correlations will allow us to study the medium properties: velocity of sound etc.
14X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Large ( ) acceptance TOF extends PID correlation studies to include:
- flavor and baryon dependent hadronization dynamics
- semi-hard processes in medium
- distinguish energy/thermal vs pressure/flow structures
PID correlations
Jana Bielcikova
15X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Energy scan: search for the critical end point
Full coverage of TOF detector is essential for the key measurements of particle ratios and <p
T> fluctuations etc.
K/ fluctuation 100K central events
Statistical error 10% 5%, with TOF
Systematics are more crucial: 1% mis-id will lead to 10% error
<p T> fluctuation 1) TOF can extend PID range to reduce uncertainty on e-by-e <p
T>
2) v2 could enhance apparent <pT> fluctuations w/o 2 coverage
Paul Sorensen
16X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
➢ PID spectra & v2
➢ PID correlations & fluctuations
➢ Lepton spectra & v2
➢ Heavy flavor spectra: pQCD test & energy loss
mechanisms
➢ Heavy flavor v2: light flavor thermalization
➢ Di-lepton pair
Achievable Physics Topics with TOF
17X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Lepton spectra --- heavy quark spectra
Well constrain on the charm total yield and spectrum
Muon at low pT
electron at intermediate pT
Haibin Zhang, Yifei Zhang, Chen Zhong
Non-photonic electron suppression ~ hadron suppression
New energy loss mechanism, e.g.collisional energy loss should be included to account for the R
AA(e).
18X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Lepton v2 --- heavy quark collectivity, light flavor thermalization
V. Greco et al., PLB 595 (2004) 202Heavy quark collectivityindicates light flavor thermalization
Electron approach:
Low pT (~1GeV/c) up to intermediate p
T
(5 GeV/c) measurement matters
Full TOF is dedicated in this direction!
Hadronic approach:
TOF+HFT will be a powerful combination
19X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
➢ PID spectra & v2
➢ PID correlations & fluctuations
➢ Lepton spectra & v2
➢ Di-lepton pair
➢ Low mass: vector mesons in medium
➢ High mass: quarkonia
Achievable Physics Topics with TOF
20X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Di-lepton – vector mesons in medium
NA60 PRL 96 (2006) 162302
spectrum is consistent with broadening peak and no mass shift
TOF+HFT upgrades will make such a measurement feasible
Low mass di-lepton spectrum Vector meson in medium
Chiral symmetry restoration --- QGP signature
21X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
Di-lepton – J/ , (2S) ...
J/ production --- QGP signature
Color screening --- suppressionCoalescence --- enhancement
L.Grandchamp et al NPA 790 (2002) 415
Difference quarkonia states
PHENIX Acceptance: | |<0.35, =2* /2 STAR full TOF Acceptance: | |<0.9, =2*
pT (e)>1.5 GeV/c
22X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
TOF provides 2 and | |<0.9 coverage
Future upgrades will benefit from or enhance the capability of this detector
.e.g. Heavy Flavor Tracker (HFT) and TOF can be a powerful device for di-lepton and heavy flavor programs
Baseline detector for future upgrades
vector mesons; quarkonia
requiring hits to reject gamma conversion bg; by measuring e+e- from the
charm background
electron ID
charm total cross section, Nbin
dca distributionbackground free
muon ID
D0, D±, DS, ΛCprecise displaced vertexhadron ID
Physics measurementsHFTTOF
23X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
STAR BUR for Run 8, 9, 10
SVT, SSD outone sector of DAQ1000
DAQ1000 ?HFT protypes
DAQ1000
TOF: 5 trays
TOF: 65 trays
TOF: Full
24X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
TOF Installation Plan
Run 8Low material, one prototype of DAQ1000
TOF: 5 trays better match the DAQ1000 prototype sector
➢Electron spectra --- charm cross section and spectrum➢PID spectra --- “Cronin” effect
Run 9DAQ1000 in preparation, HFT prototypes
TOF: 65 trays by FY2008 Q4
Comprehensive measurements on PID spectra, v2, HBT, correlations
fluctuations in Au+Au 200 GeV collisions➢Di-lepton spectrum --- vector mesons in medium➢Direct D reconstruction with TOF+HFT --- one big step!
Run 10DAQ1000 ready
TOF: full coverage
Comprehensive measurements on PID spectra, v2, HBT, correlations,fluctuations at low energy colllisions➢Freeze-out characteristics➢Fluctuations --- search for critical end point
25X. Dong / LBNLAug. 2nd, 2007, DOE TOF Review, BNL
TOF Publications
✔ Identified particle elliptic flow in Au+Au 62 GeV, PRC 75 (2007) 054906✔ Identified baryon and meson distributions at large transverse momenta from
Au+Au collisions at 200 GeV, PRL 97 (2006) 152301✔ PID Cronin Effect in d+Au, PLB 616 (2005) 8.✔ Charm Cross section and spectra in p+p, d+Au, PRL 94 (2005) 062301.✔ Lots of conference proceedings, QM04, SQM04, QM05, SQM06, QM06 talks. ✔ 4 Ph. D theses.✔ 9 NIMA publications:
Nucl.Instrum.Meth.A538:243-248,2005 Nucl.Instrum.Meth.A533:60-64,2004 Nucl.Instrum.Meth.A492:344-350,2002 Nucl.Instrum.Meth.A508:181-184,2003 Nucl.Instrum.Meth.A478:176-179,2002Nucl.Instrum.Meth.A538:425-430,2005 Nucl.Instrum.Meth.A537:698-702,2005 Nucl.Instrum.Meth.A547:334-341,2006
Nucl.Instrum.Meth.A558:419,2006
➢ 2 Ph. D. theses
✔ More to come from prototype TOFrs 2 STAR papers in preparation