LargeHadronElectronColliderProgressReporttoECFA

MaxKlein

fortheLHeCGroup

ECFAatCERNGeneva27.November2009

www.lhec.cern.ch

Electron-Nucleon Scattering

at the Tera ScaleCERN-ECFA-NuPECC: Preparing a Conceptual Design Report on the LHeC

The Large Hadron Electron Collider (LHeC) is a new colliding beam facility, based on the LHC at CERN, exploiting Tera scale cms energies in the electron-quark system in order to pursue a rich and luminous programme of inelastic, polarised electron/positron -proton, deuteron and heavy ion scattering measurements. By reaching momentum transfer squared values of Q2 above 106 GeV2 and correspondingly low values of Bjorken x, the LHeC is seen as a natural complement to the LHC and to an envisaged new lepton collider. This poster illustrates part of the still ongoing work on the machine, interaction region and detector designs as well as on the

physics potential of the LHeC at high scales, high parton densities and with high precision eq measurements. This work, pursued in a wide international collaboration under the auspices of CERN, ECFA, NuPECC and a Scientific Advisory Committee, is directed to a Conceptual Design Report by 2010, as part of the deliberations of the HEP community on its future programme of exploring the energy frontier with accelerators, which is reminiscent to the exploration of the Fermi scale with HERA, the Tevatron and LEP. More information on the LHeC is collected at www.lhec.org.uk. The next workshop will be held at Divonne 1-3.9.2009.

LHeC Physics and Kinematics - Kinematic plane in Bjorken-x and resolving power Q2 , showing the coverage of fixed-target experiments, HERA and the LHeC. The mapping of the planned physics programme onto this plane is also indicated.

Direct Measurement of Partons - The LHeC permits the complete resolution of the light and heavy quark structure of the nucleon. It will make precision measurements of the beauty density, the first ever measurements of strange and anti-strange quark densities or the u/d densities at low and at large x . The LHeC is a single top and anti-top-quark factory.

LHeC as Ring-Ring Collider - The LHeC as a Ring-Ring Collider may use the SPL as an injector and will have bypasses around LHC experiments, in which the rf may be placed. A new type of dipole magnet is considered for installation on top of the proton ring. The luminosity is estimated to be above 1033cm-2s-1 with an assumed limit of 100 MV wall plug power.

Saturation of Parton Densities - At small Bjorken x the rise of the parton densities is predicted to be limited by unitarity. A new phase of matter appears governed by modified parton dynamics with relations to nuclear and neutrino astrophysics. This may be discovered in ep with precision measurements of F2 and FL , vector meson measurements or di!ractive scattering in a hitherto unexplored range of phase space and phenomena.

Lepton-Proton Scattering - Comparison of the energies and luminosities of selected previous (blue) and proposed future (red) lepton–proton scattering facilities. The LHeC moves DIS into the Terascale with about 100 times the luminosity of HERA.

Complementing the LHC - The LHeC complements the LHC with precision measurements e.g. on the gluon density or the investigation of the Higgs. With the LHeC, new physics phenomena possibly occurring at the LHC can be distinguished reliably from mere variations of partonic behaviour, currently subject to extrapolation and parameterisation uncertainties.

A New Detector for ep/eA - The detector is modular for fast installation down the pit and to cope with the requirements of high luminosity and of large acceptance near the beam axis. Design work is ongoing on the interaction region to allow for simultaneous operation of pp (LHC) and ep (LHeC) beams.

New Physics in eq Scattering - Singly produced new states, such as eq resonances or excited leptons, have a much higher cross section at an ep machine than in pp, which will allow the determination of quantum numbers of new states and possibly give access to a complementary phase space. If leptons and hadrons are ‘one form of matter’ (A.Salam), an eq collider is most suited for its exploration.

Resolving Proton’s Structure - Distance scales resolved in successive lepton–hadron scattering experiments since the 1950s, and some of the new physics revealed. The LHeC will resolve distances below 10-19m, more than a 10.000 times smaller than the proton’s radius and 10 times below HERA.

Exploring Multi-TeV Scales - Exploration of ultrahigh energy scales with precision measurements in electroweak and strong interactions. Precision determination of light quark weak neutral current couplings.Unification of coupling constants at the Planck scale may be tested with alpha_s measured an order of magnitude more accurately than so far.

LHeC as Linac-Ring Collider - The LHeC as a Linac-Ring Collider is considered to possibly use a racetrack arrangement of ILC type superconducting cavities. The luminosity is in excess of 1032cm-2s-1 with a power limit of 100MW, based on the sLHC upgrade. It may be enlarged with energy recovery techniques. The luminosity diminishes as 1/E with the electron beam energy and the linac may therefore surpass the energy reach of the ring.

Partonic Structure of Nuclei - The LHeC extends the experimental knowledge on the partonic structure of nuclei by nearly 4 orders of magnitude in DIS. The predicted enhancement of the gluon density ~A1/3 and the very high energies at the LHeC allow parton saturation e!ects to be studied both in ep and eA interactions and thus to uniquely separate nuclear from unitarity e!ects in deep inelastic scattering.

Compiled by M.Klein and F.Marcastel - 10 July 09

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10 210 310 410 510 610 710 810 9

1 10 10 2 10 3cms Energy (GeV)

Lum

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!"#$%&$'()*'+(),- 'New Physics

Precision QCD andElectroweak Physics

NuclearStructure

& Dynamics

High Parton Densities

Large xPartons

100

1960 1980 2000 2020year

10–15 m

10–20 m

10–1

10–2

10–3

10–4

10–5

dist

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(fm

)

SLAC

SLAC

FNAL

CERNquark–gluon

dynamics

DESYHERA

?

quarks

finite protonsize

CERNLHeC

LHeC total cross sections (MC simulated)

10 -3

10 -2

10 -1

1

10

10 2

10 3

10 4

10 5

10 6

10 10 2 10 3

charm p

charm DIS

beauty pbeauty DIS

tt ptt DIS

bW tbW tbar

CC e+p

sW cCC e-p

sW cbar

Elep (GeV)

(pb)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

10 -5 10 -4 10 -3 10 -2 10 -1

unce

rtain

ty o

n d/

u

Q2 = 4 GeV2

H1 + BCDMS

LHeC ep

LHeC ep+ed

(relaxed low x assumptions in the fit)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

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10 -5 10 -4 10 -3 10 -2 10 -1

x

unce

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Q2 = 1000 GeV2

CTEQ 61

LHeC simulation, 10 fb-1

, GeV/cjjM0 20 40 60 80 100 120 140 160 180 2000

100

200

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jjM

-1 -0.5 0 0.5 1-1

-0.5

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1.5 LHeC scenario D ZEUS fit H1 prel. (HERA I+II 94-05)

SM CDF LEP

-1 -0.5 0 0.5 1-1

-0.5

0

0.5

1

1.5

da

dv

68% CL

HERA+LHeC fit

-1 -0.5 0 0.5 1-1

-0.5

0

0.5

1

1.5 LHeC scenario D ZEUS fit H1 prel. (HERA I+II 94-05)

SM CDF LEP

-1 -0.5 0 0.5 1-1

-0.5

0

0.5

1

1.5

uauv

68% CL

HERA+LHeC fit

Luminosity LHeC Ring-Ring

0

1

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3

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30 40 50 60 70 80 90 100Energy(e)/GeV

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Luminosity LHeC Linac-Ring

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1

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1e-06 1e-05 0.0001 0.001

F L(x.

Q2 )

x

L at the LHeC - Simulated data from FS04 saturation mode

LHeC simulated dataNNPDF1.0

10 3

10 4

10 5

10 6

10 7

10 8

0 50 100 150 200 250

LHeC (2 fb-1)HERA (500 pb-1)

Diffractive event yield (xIP < 0.05, Q2 > 1 GeV2)

MX / GeV

Even

ts Fermion number determination

LQ Mass (GeV)

Asym

met

ry LHeC, 1 fb-1

Ee = 140 GeV

LHC, 100 fb-1

Scalar LQ = 0.3

0

0.2

0.4

0.6

0.8

1

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200 400 600 800 1000 1200 1400 1600 1800 e* Mass [ GeV ]200 400 600 800 10001200140016001800

-4

-3

-2

e* Mass [ GeV ]200 400 600 800 10001200140016001800

-4

-3

-2

=758 GeV)s (LHeC: e=1.4 TeV)s (LHeC: e=1.9 TeV)s (LHeC: e

LEPHERA: all channels

+eeLHC: e

x-610 -510 -410 -310 -210 -110 1

)2 (G

eV2 Q

-110

1

10

210

310

410

510

610 )2(x,Q2,Anuclear DIS - FProposed facilities:

LHeCeRHIC

Fixed-target data:NMCE772E139E665EMC

(Au, b=0 fm)2sQ

perturbative

non-perturbative

(70 GeV - 2.5 TeV)

(10 GeV - 100 GeV)

e-Pb (LHeC)

e-Au (eRHIC)

PosteratEPS09andLepton‐Photon09

Kinema8csandRecentDevelopments

2008

SeptemberDivonneworkshop;NuPECCMeeKngatGlasgow

OctoberICFASeminaratSLAC

NovemberECFAPlenaryatCERN

DecemberConvenor’sMeeKngatCERN

2009

MarchVisittoSLAC[Linac]

AprilDIS09atMadrid:LHeCpremeeKng,parallel,SACplenarypanel(M.K.arXiv:0908.2877[hep‐ex])

AprilPAC09atVancouver‐Papers,Talk,Proceedings

MayVisittoBINPNovosibirsk[RingMagnets]

JuneLowx/HPDmeeKngatCERN,pre‐Blois

SeptemberDivonneII(CERN‐ECFA‐NuPECCWorkshop)~80talksfrom~100parKcipants

OctoberNuPECCLongRangePlanningWorkshop

CDRExtendedversionbyMidDecember09

PhysicsProgrammeoftheLHeC

+Unfoldingcompletelythepartonstructureoftheproton(andoftheneutronandphoton)andsearchforsub‐substructuredownto610‐20m

+ExploraKonofnewsymmetriesandthegrandunifica8onofparKcleinteracKonswithelectroweakandstronginteracKonmeasurementsofunprecedentedprecision.

+SearchforandexploraKonofnew,Terascalephysics,inparKcularfornewstateswithleptonqu.numbers(RPVSUSY,LQ,excitedfermions),complementarytotheLHC

+ExploraKonofhighdensitymaPer[lowxphysicsbeyondtheexpectedunitaritylimitforthegrowthofthenucleongluondensity]

+UnfoldingthesubstructureandpartondynamicsinsidenucleibyanextensionofthekinemaKcrangebyfourordersofmagnitude[iniKalstateoftheQGP]

Largeamountofstudiesdoneandongoing,withoutaimingatcompletelist.Followsanexampleperpointeach.Notethatthesearefinalwhenwriienup.

StrangeandAn8‐StrangeQuarkDistribu8ons

€

W −sbar→ cbar1 fb−1

εc = 0.1εq = 0.01δsyst = 0.1

−ϑ h ≥1o

•−ϑ h ≥10o

NotmeasuredwithH1,ZEUSHERMES(NK):smuchlarger?Dimuondata:s≠sbar?

W,ZsensiKvetos

LHeC:measurebothstrangeandan8‐swithhighprecisionforthefirst8me

HER

MES,K.Rith

EPS09

Q2~1GeV2

HighPrecisionElectroweakPhysics

Precisionmeasurementofweakneutralcurrentcouplings(+pdf’s):accesstonewelectroweakphysics.

40TeVlimitsonContactInterac8onsandcorrespondinglyonextradimensions

Gluon‐SMHiggs

InSMHiggsproduc8onisgluondominated

LHeC:hugex,Q2rangeforxgdetermina8on

WWtoHiggsfusionhassizeableepxsec8on

CTEQBelyayevetal.JHEP0601:069,2006

CfDivonne09forQCDbgdstudies+btagging

Beauty‐MSSMHiggs

InMSSMHiggsproduc8onisbdominated

FirstmeasurementofbatHERAcanbeturnedtoprecisionmeasurement.

LHeC:higherfrac8onofb,largerrange,smallerbeamspot,bePerSidetectors

CTEQBelyayevetal.JHEP0601:069,2006

DiscoveryofPartonSatura8on–ep,lowx

Fullsimula8onofF2andFLBothtogethermustrevealsatura8on

NuclearStructureandDynamics

ExtensionofQ2,1/xrangeby104

FermimoKon‐‐ptaggingShadowing‐‐diffracKon

p,D,Ca,Pbbeams

Completedetermina8onofnPDFsintononlinearregimeLHeCisboundtodiscoverpartonsatura8onineAANDep

AcceleratorandDetectorDesign

CollaboraKonsofCERNwithexpertsfromCockcrop,BNL,DESY,KEKLausanne,Novosibirsk,SLAC,TAC

20workpackageswithidenKfiedresponsibles

Ring‐Ringep/eA

Ee=10…70GeV.Lep~1033cm‐2s‐1(100KmesHERA)

Injector:dedicatedorSPLbased.

DetailedfirstdesignstudyinJINSTP1001(2006)

RRLuminosityandParameters

€

L =Npγ

4πeεpn⋅

Ieβ pxβ py

= 8.31032 ⋅ Ie50mA

mβ pxβ pn

cm−2s−1

€

Ie = 0.35mA ⋅ PMW

⋅100GeV

Ee

4

Luminosityfore±psafelyabove1033cm‐2s‐1

Used“ul8mate”LHCbeamparameters

Energylimitedbyinjec8onandsyn.radlosses

Powerlimitsetto100MW

Smallptuneshie:simultaneousppandep

eRing–Op8cs

βfuncKonsforLHeC‐2008

Dispersionwas50‐90cm

andhoriz.emiiance22nm

38460mlongcells

2009:opKmisaKonofFODOcell

Dispersionreducedto20‐50cm

emiianceεx=7.5nmεy=3.7nm

MEDIUMorWEAKBENDSOLUTION

“inner”tripletfocusβx=7.1cmβy=12.7cm

Op8csinthearcs

Op8misa8onongoing

Minibetadesign

DipoleMagnets

LEP

O‐shapedmagnetwithferritecore[BINP‐CERN] PrototypedesignunderwayatNovosibirsk,May2010

Accelerator LEP LHeC

CrossSec8on/cm2 50x50 20x10

Magne8cfield/T 0.02‐0.11 0.02‐0.135

EnergyRange/GeV 20‐100 10‐70

GoodFieldArea/cm2 5.9x5.9 6x3.8

FODOlength/m 76 53

Magnetlength/m 2x34.5 2x14.76

segmenta8on 6cores 14

Numberofmagnets 736 488

Weight/kg/m 800 240

Ring–Workinprogress

Interac8onregiondesign

Installa8onstudy

SystemaKcinvesKgaKonofclasheswithLHCinstallaKonandpossibleways‘around’

InstallaKonsequence‐Kmeline

Polarisa8on

TwoLINACConfigura8ons[CERN‐SLAC]

60GeV31MV/m,pulsedtwopasses

60GeV13MV/mCWERL4passes

140GeV31MV/m,pulsed2passes

LINAC‐RingParameters

€

Np =1.7 ⋅1011,εp = 3.8µm,β* = 0.2m,γ = 7000 /0.94

L = 8 ⋅1031cm−2s−1 ⋅Np10

−11

1.7⋅0.2β* /m

⋅P /MWEe /GeV

Configura8on 60GeV,pulsed 60GeVCWERL 140GeVpulsed

Ne/bunch/109/50ns

4 1.9 2

gradientMV/m 32 13 32

normalisedε/μm 50 50 100

cryopower/MW 3 20 6

effecKvebeampower/MW

50 40/(1‐ηERL) 50

Luminosityforul8matebeam

TheLRcombinaKonyetrequiresasKllbeierpbeamor/andEerecoverytocometoluminositybeyond1032cm‐2s‐1

eOp8csforLINAC

2passes 4passes‐ERL

βx,yβx,y

LINAC‐WorkinProgress

IROp8ons:

Headondipoles

CrossinglikeRRIR

Positronsource

Difficulttoreachhighintensity.Perhapsbestsuited:hybridtargetproducKonofunpolarisedpositrons.SeveralstaKons?cfDivonne

LHeCDetectorversionforlowxandeAMuonchambers(fwd,bwd,central)

Coil(r=3ml=11.8m,3.5T)[ReturnFenotdrawn,2coilsw/oreturnFestudied]

CentralDetectorPixelsEllipKcbeampipe(~3cm‐orsmaller)

Silicon(fwd/bwd+central)[Stripor/andGasonSlimmedSiPixels][0.6mradiusfor0.03%*ptin3.5Tfield]

El.magn.Calo(Pb,Scint.9‐12X0)HadronicCalo(Fe/LAr;Cu/Brass‐Scint.~30λ)

FwdDetectors(downto1o)SiliconTracker[Pix/Strip/Strixel/PadSiliconor/andGasonSlimmedSiPixels]

Calice(W/Si);dualReadOut‐ElmCaloFwdHadrCalo:Cu/Brass‐ScinKllator

BwdDetectors(downto179o)SiliconTracker[Pix/Strip/Strixel/PadSiliconor/andGasonSlimmedSiPixels]

Cu/Brass‐ScinKllator,Pb‐ScinKllator(SpaCal‐hadr,elm)

ExtensionsinfwddirecKon(tagp,n,d)andbackwards(e,γ)understudy.

Comple8onoftheCDR AcceleratorDesign[RRandLR]

OliverBruening(CERN),

JohnDainton(CI/Liverpool)

Interac8onRegionandFwd/Bwd

BernhardHolzer(DESY),

UweSchneeekloth(DESY),

PierrevanMechelen(Antwerpen)

DetectorDesign

PeterKostka(DESY),

RainerWallny(UCLA),

AlessandroPolini(Bologna)

NewPhysicsatLargeScales

GeorgeAzuelos(Montreal)

EmmanuellePerez(CERN),

GeorgWeiglein(Hamburg)

PrecisionQCDandElectroweak

OlafBehnke(DESY),

PaoloGambino(Torino),

ThomasGehrmann(Zuerich)

ClaireGwenlan(Oxford)

PhysicsatHighPartonDensi8es

NestorArmesto(SanKago),

BrianCole(Columbia),

PaulNewman(Birmingham),

AnnaStasto(PennState)

OliverBruening(CERN)JohnDainton(Cockcrop)AlbertDeRoeck(CERN)StefanoForte(Milano)MaxKlein‐chair(Liverpool)PaulNewman(Birmingham)EmmanuellePerez(CERN)WesleySmith(Wisconsin)BerndSurrow(MIT)KatsuoTokushuku(KEK)UrsWiedemann(CERN))

GuidoAltarelli(Rome)SergioBertolucci(CERN)StanBrodsky(SLAC)AllenCaldwell‐chair(MPIMunich)SwapanChaiopadhyay(Cockcrop)JohnDainton(Liverpool)JohnEllis(CERN)JosEngelen(CERN)JoelFeltesse(Saclay)LevLipatov(St.Petersburg)RolandGaroby(CERN)RolandHorisberger(PSI)Young‐KeeKim(Fermilab)AharonLevy(TelAviv)KarlheinzMeier(Heidelberg)RichardMilner(Bates)JoachimMnich(DESY)StevenMyers,(CERN)TatsuyaNakada(Lausanne,ECFA)GuenterRosner(Glasgow,NuPECC)AlexanderSkrinsky(Novosibirsk)AnthonyThomas(Jlab)StevenVigdor(BNL)FrankWilczek(MIT)FerdinandWilleke(BNL)

Scien8ficAdvisoryCommiPee

SteeringCommiPee

WorkingGroupConvenors

1.  Finalisephysicsandtechnicalstudies2.  DIS10Firenze[April]andIPACCJapan[May]3.  DrapCDRJune20104.  DivonneIII–UpdatesandDiscussionwithreferees5.  November10:FinalreporttoECFA6.  SubmitCDRtoCERN,ECFA,NuPECC

LHeCreliesonexper8seandenthusiasmofmanycolleaguesandsupportbyECFA,NuPECCandCERN

Stepstogoin2010

LHeCbarack561

Backupslides

Quark‐GluonDynamics‐Diffrac8onandHFS(fwdjets)

Diffrac8ontoaccompany(SUSY)HiggsfwdphysicsatLHC

Understandmul8‐jetemission(unintegr.pdf’s),tuneMC’sAtHERAresolvedγeffectsmimicnon‐ktorderedemissionCrucialmeasurementsforQCD,andforQCDattheLHC

HERA

P.Newman,DIS07

H.Jung,L.Loennblad,THERAstudy

E. Perez LHeC Workshop, Sep 09

Determina8onofLQproper8esinsingleproduc8on:e.g.FermionNumber

Inpp:lookatsignalseparatelywhenresonanceisformedby(e++jet)and(e‐+jet):

SignoftheasymmetrygivesF,butcouldbestaKsKcallylimitedatLHC.(*)

Easierinep!Justlookatthesignalwithincidente+andincidente‐,buildtheasymmetrybetweenσ(e+in)andσ(e

‐in).

σ(e+out)>σ(e‐out)

forF=0

e+

q

g

q e‐

F=0

• λ

e‐

q

g

q e‐

__

F=0

• λ

IfLHCobservesaLQ‐likeresonance,M<1‐1.5TeV,LHeCcoulddetermineFifλnottoosmall.

(*)Firstroughstudydoneforthe2006paper.Needtocheck/refinewithafullanalysisofsignalandbackgrounds.

Quark‐GluonDynamics(satura8on,GPDs)‐ep

LHeCopensphasespacetodiscoversatura8oninDIS

Highluminosity,polarisa8on,accuracyforGPD’s(DVCS)

P.Newman,L.Favart,DIS08

J.BartelsatDivonneonlowxtheoryJ.Forshawetal,DIS08

Divonne08

StrongCouplingConstantαsleastknownofcouplingconstantsGrandUnificaKonpredicKonssufferfromδαs

DIStendstobelowerthanworldaverage

LHeC:permilleaccuracyindep.ofBCDMS.Challengetoexperimentandtoh.o.QCD

SimulaKonofαsmeasurementatLHeC

1/α

MSSM‐B.Allnachetal,hep‐ex/0403133

finestructure

weak

strong

NewPhysicsintheeqSector

?LQ,RPVSUSYSpectroscopy

?Excitedfermions

28Exactknowledgeofpdf’smaybecrucialtounderstandCI’s