Parity Violation in eP Scattering at JLab - Experimental Hall A宇稱在JLab實驗大廳散射EP

ParityandtheJLab12GeVUpgrade:

TheProgramforHallAHadronicandElectroweakPhysicsMollerandDISParityP.A.

SouderSyracuseUniversityThankstoBosted,Brodsky,Kumar,Londergan,Meziani,Michaels,Reimer,Ramsey-Musolf,Paschke,Pitt,ZhengJune24,2005OutlineParity-ViolatingElectronScatteringBriefOverviewWeakNeutralCurrentInteractionsatQ2<<MZ2Parity-ViolatingM?llerScatteringUltimatePrecisionatQ2<<MZ2:25TeVReachComplementarytoQweakParity-ViolatingDeepInelasticScatteringNewPhysicsat10TeVinSemileptonicSectorChargeSymmetryViolationd/uatHighxHigherTwistEffectsJune24,2005Thecouplingsgdependonelectroweakphysicsaswellasontheweakvectorandaxial-vectorhadroniccurrentWithspecificchoiceofkinematicsandtargets,onecanprobenewphysicsathighenergyscalesWithotherchoices,onecanprobenovelaspectsofhadronstructure(gAegVT

+

gVegAT)PVAsymmetriesWeakNeutralCurrent(WNC)InteractionsatQ2<<MZ2LongitudinallyPolarizedElectronScatteringoffUnpolarizedFixedTargetsJune24,2005APVMeasurementstoAPV~0.1to100ppmSteadyprogressintechnologypartperbillionsystematiccontrol1%normalizationcontrolJLabnowtakestheleadNewresultsfromHAPPEXPhotocathodesPolarimetryTargetsDiagnosticsCountingElectronicsE-05-007e2eJune24,2005TheStandardModelJune24,2005TheAnnoyingStandardModelRareorForbiddenProcessesSymmetryViolationsElectroweakOne-LoopEffects-Doublebetadecay..-neutrinos,EDMs..-Muong-2,betadecay..NuclearPhysicsLongRangePlan:Whatisthenewstandardmodel?Precisepredictionsatlevelof0.1%IndirectaccesstoTeVscalephysicsExtraprobeofhadronsLowQ2offersuniqueandcomplementaryprobesofnewphysics(itjustwontbreak!)G0InputOutputJune24,2005World

Electroweak

Data

onsin2θWPerhapstherearebiggerdeviationslurkingelsewhere???

Are

LeptonicandhadronicZcouplingsseeminconsistent?MostexpertsseetheprecisiondataasremarkablyconsistentJune24,2005ElectroweakPhysicsatLowQ2LEPII,Tevatron,LHCaccessscalesgreaterthanL~10TeVLogicaltopushtohigherenergies,awayfromtheZresonanceQ2<<scaleofEWsymmetrybreakingParityViolatingvsParityConservingComplementary:June24,2005WNCLowQ2ProcessesLimitedbytheory:Atomicstructure;NeutronHaloPVDISexperimentfeasiblewithinscopeofHMS/SHMSupgradeUnique,complementaryprobesofNewPhysicsTheoreticalissuesareinterestinginthemselves:ReactorexperimentcannotdobetterthanSLACE158DedicatednewapparatusatupgradedJLabcandosignificantlybetter:Unique,outstandingopportunityforadedicatedapparatuswithJLabupgradeAPVonCsAtomicParityViolation(APV)NuTeVSemi-LeptonicE158LeptonicseriesofisotopesPVDeepInelasticScatteringatupgradedJLabPVElasticelectron-protonscatteringatJLabQweak

-escatteringinreactorM?llerscatteringatupgradedJLabBestlowenergymeasurementuntilLinearCollideror-FactoryJune24,2005FixedTargetM?llerScatteringPurelyleptonicreactionWeakchargeoftheelectron:QWe~1-4sin2

W

Maximalat90oinCOM(E’=Elab/2)

HighestpossibleElab

withgoodP2I

ModerateElabwithLARGEP2IFigureofMeritriseslinearlywithElabSLACE158Jlabat12GeVUnprecedentedopportunity:ThebestprecisionatQ2<<MZ2withtheleasttheoreticaluncertaintyuntiltheadventofalinearcollideroraneutrinofactoryJune24,2005PresentResultsandFutureExperimentsJune24,2005Qeweak:ElectronWeakCharge–SLACE158ExperimentParity-violatingMollerscatteringQ2~.026GeV2

~4–7mradE~48GeVatSLACEndStationAFinalresults:hep-ex/0504049APV=-13114(stat)10(syst)ppbsin2

eff(Q2=0.026GeV2)=

0.2397±0.0010±0.0008Runningofsin2

effestablishedat6levelinpureleptonicsectorJune24,2005Designfor12GeVE’:3-6GeV

lab=0.53o-0.92oAPV=40ppbIbeam=90μA150cmLH2targetBeamsystematics:steadyprogress(E158RunIII:3ppb)Focusalleviatesbackgrounds:epep(),epeX()Radiation-hardintegratingdetectorNormalizationrequirementssimilartootherplannedexperimentsCryogenics,densityfluctuationsandelectronicswillpushthestate-of-the-artToroidalspectrometerringfocus4000hours(APV)=0.58ppbMack,Reimer,atalJune24,2005NewPhysicsReach

ee~25TeVJLabM?ller

ee~15TeVLEP200NewContactInteractionsDoesSupersymmetry(SUSY)provideacandidatefordarkmatter?LightestSUSYparticle(neutralino)isstableifbaryon(B)andlepton(L)numbersareconservedHowever,BandLneednotbeconservedinSUSY,leadingtoneutralinodecay(RPV)Examples:Kurylov,Ramsey-Musolf,SuJune24,2005Region3:

VerticalDriftchambersRegion2:HorizontaldriftchamberlocationRegion1:GEMGasElectronMultiplierQuartzCherenkovBars(insensitivetonon-relativisticparticles)CollimatorSystemMini-torusQTORMagnetTriggerScintillatorLumiMonitorse-beamTheQweakApparatus

(CalibrationModeOnly-Production&CalibrationModes)Ebeam=1.165GeVIbeam=180μAPolarization~85%Target=2.5KWJune24,2005JLabQweakRunI+II+III(preliminary)

±0.006(proposed)-

QweakmeasurementwillprovideastringentstandaloneconstraintonLepto-quarkbasedextensionstotheSM.

Qpweak

(semi-leptonic)andE158(pureleptonic)togethermakeapowerfulprogramtosearchforandidentifynewphysics.SLACE158Qpweak&Qeweak–ComplementaryDiagnosticsforNewPhysics

June24,2005Whatabouttherunningofsin2

W?RunningcouplingconstantsinQEDandQCDQED(runningof)

sQCD(runningof

s)137

June24,2005Runningofsin2θWQWemodifiedsin2

WrunswithQ2

JLabmeasurementwouldhaveimpactondiscrepancybetween

leptonicandhadronicZ-polemeasurements(sin2

W)~0.0003ComparabletosinglecollidermeasurementsJune24,2005ParityViolationinDeepInelasticScatteringJune24,2005Electron-QuarkPhenomenologyC1uandC1dwillbedeterminedtohighprecisionbyQweak,CsC2uandC2daresmallandpoorlyknown: onecombinationcanbeaccessedinPVDISNewphysicssuchascompositeness,newgaugebosons:DeviationstoC2uandC2dmightbefractionallylargeAVVAProposedJLabupgradeexperimentwillimproveknowledgeof2C2u-C2dbymorethanafactorof20June24,2005ParityViolatingElectronDISfi(x)arequarkdistributionfunctionse-NXe-Z*

*Foranisoscalartargetlike2H,structurefunctionslargelycancelintheratio:ProvidedQ2>>1GeV2andW2>>4GeV2andx~0.2-0.4MustmeasureAPVtofractionalaccuracybetterthan1%11GeVathighluminositymakesveryhighprecisionfeasible

JLabisuniquelycapableofprovidingbeamofextraordinarystabilitySystematiccontrolofnormalizationerrorsbeingdevelopedat6GeVJune24,20052HExperimentat11GeVE’:5.0GeV±10%

lab=12.5oAPV=217ppmIbeam=90μA60cmLD2targetUsebothHMSandSHMStoincreasesolidangle~2MHzDISrate,π/e~2-3xBj~0.235,Q2~2.6GeV2,W2~9.5GeV21000hours(APV)=0.65ppm(2C2u-C2d)=±0.0086±0.0080PDG(2004):-0.08±0.24Theory:+0.0986Advantagesover6GeV:HigherQ2,W2,f(y)Lowerrate,betterπ/eBettersystematics:0.7%June24,2005PhysicsImplicationsExamples:1TeVextragaugebosons(modeldependent)TeVscaleleptoquarkswithspecificchiralcouplingsUnique,unmatchedconstraintsonaxial-vectorquarkcouplings: ComplementarytoLHCdirectsearches(2C2u-C2d)=0.012(sin2

W)=0.0009June24,2005WhyshouldwebelieveDISparity

whennooneBelievesNuTeV?June24,2005Measuringsin2θWwithNuTeVPaschos&Wolfenstein(PRD7,91(73)):PWratio

minimizessensitivitytoPDFs,higher-ordercorrectionsResultisoffby2.8σJune24,2005TheNuTeVExperimentFeaturesverylargekinematicacceptanceChargedcurrentμNeutralcurrentJune24,2005PWRatiodependsonthefollowingassumptions:

Isoscalartarget(N=Z)includeonlylight(u,d)quarksneglectheavyquarkmassesassumeisospinsymmetryforPDFsnonucleareffects(partonshadowing,EMC,….)nohighertwisteffects

radiativecorrectionsOK?(γ-Wboxes?)nocontributionsoutsideStandardModelAssumptionsforthePaschos-WolfensteinRatioNobodybelievesthatthisistheproblemJLab12GeVissuesJune24,2005PVDIScanAddressIssuesRaisedbyNuTeVAnalysisassumedcontrolofQCDuncertaintiesHighertwisteffectsChargeSymmetryViolation(CSV)d/uathighxNuTeVprovidesperspectiveResultis3fromtheorypredictionGeneratedalivelytheoreticaldebateRaisedveryinterestingnucleonstructureissues:cannotbeaddressedbyNuTeVJLabat11GeVoffersnewopportunitiesPVDIScanaddressissuesdirectlyLuminosityandkinematiccoverageOutstandingopportunitiesfornewdiscoveriesProvideconfidenceinelectroweakmeasurementJune24,2005SearchforCSVinPVDISSensitivitywillbefurtherenhancedifu+dfallsoffmorerapidlythanu-dasx1measureorconstrainhighertwisteffectsatx~0.5-0.6precisionmeasurementofAPVatx~0.7tosearchforCSVStrategy:u-dmassdifferenceelectromagneticeffectsDirectobservationofparton-levelCSVwouldbeveryexciting!Importantimplicationsforhighenergycollider

pdfsCouldexplainsignificantportionoftheNuTeVanomalyForAPVinelectron-2HDIS:June24,2005PhenomenologicalPartonCSVPDFsMRSTPhenomenologicalPDFsincludeCSVfor1sttime:Martin,Roberts,Stirling,Thorne(03):ChooserestrictedformforpartonCSV:Bestfit:κ=-0.2,largeuncertainty!BestfitremarkablysimilartomodelCSVpredictionsMRSTADEL[f(x):0integral;matchestovalenceatsmall,largex]90%conflimit(κ)June24,2005HigherTwistCoefficientsinparity

conserving(Di)andnonconserving(Ci)ScatteringAPVsensitivetodiquarks:ratioofweaktoelectromagneticchargedependsonamountofcoherenceIfSpin0diquarksdominate,likelyonly1/Q4effectsSomehighertwisteffectsmaycancelinratio,soAPVmayhavelittledependenceonQ2.

(DoesnotEvolve)June24,2005GoingfromLOtoNNNLOGreatlyReduces

theExtractedHigherTwistCoefficientsxD(x)D(x)Q2minD/Q2min(%)D/Q2min(%)LONNNLOLONNNLO0.1-0.2-.0070.0010.5-1420.2-0.3-.110.0031.0-110.00.3-0.4-.06-0.0011.7-3.5-0.50.4-0.5.220.112.6840.5-0.6.850.393.822100.6-0.72.61.45.845240.7-0.87.34.49.47847F2(x,Q2)=F2(x)(1+D(x)/Q2)Q2=(W2-M2)/(1/x-1)Q2min=Q2(W=2)IfD(x)~C(x),ParitymightshowhighertwistAthighxwithoutneedingQCDevolution.June24,2005APVinDISon1HDeterminethathighertwistisundercontrolDeterminestandardmodelagreementatlowxObtainhighprecisionathighxAllowsd/umeasurementonasingleproton!Vectorquarkcurrent!(electronisaxial-vector)+smallcorrectionsJune24,2005Uncertaintiesind/uatHighx,andtheErrorsweWouldLiketoAchievewithPVMeasurementsDeuteronanalysishasnuclearcorrectionsAPVfortheprotonhasnosuchcorrectionsMustsimultaneouslyconstrainhighertwisteffectsThechallengeistogetstatisticalandsystematicerrors~2%June24,2005CompletePVDISProgram(Including12GeV)HydrogenandDeuteriumtargetsBetterthan2%errorsItisunlikelythatanyeffectsarelargerthan10%W2wellover4GeV2Q2rangeafactorof2foreachxpoint(Exceptx~0.7)ModeraterunningtimesWithHMS/SHMS:searchforTeVphysicsWithlargersolidangleapparatus:highertwist,CSV,d/u…June24,2005ApparatusNeededforPVDISJune24,2005Asymmetrytobemeasured:R.Michaels(JLab),P.Reimer(ANL),X.Zheng(ANL)

andtheHallACollaborationExperimentalSetup:85uA,6GeV,“parity-quality〞80%pol.beam;25-cmLD2target;TwoHRSdetectscatteredelectrons.MeasureAdatQ2=1.10andQ2=1.90(GeV/c)2to2%(stat.);E05-007:StartPVDISat6GeV(Approved)June24,2005FromAdatQ2=1.90(GeV/c)2,canextract(2C2u-C2d)toanuncertaintyof0.03(factorof8improvementcomparedtoPDG);provideconstraintsonnewphysics&testoftheStandardModelupto1TeVmasslimit;Z'Searches:Compositeness(4-fermioncontacts)Leptoquarks.TheAdatQ2=1.10(GeV/c)2willhelptoinvestigateiftherearesignificanthadronic(higher-twist)effects:(12GeV,NuTeV...)Goalsat6GeVJune24,2005ReachingLargexandLargeQ2at12GeV50%azimuthalcoverageassumed6GeVNeedLargeθforlargexandQ2HMSandSHMSarefineforsmallθJune24,20052to3.5GeVscatteredelectrons20to40degreesFactorof2inQ2rangeatmoderatexHighstatisticsatx=0.7,withW>2June24,2005Cuton0.6<y<0.8

LargerangeinQ2forHTstudyHighx(>0.7)accessiblewithW2>4Largeacceptanceallowsfeasibleruntimerequests

p/eratioisnotextreme,butcannotintegrateDetailsonKinematicsandπ/eBackgroundsJune24,2005LargeAngleLargeAcceptance:ConceptCW90μAat11GeV40-60cmliquidH2andD2targetsLuminosity>1038/cm2/sJLabUpgradeNeedhighratesathighxForthefirsttime:sufficientratestomakeprecisionPVDISmeasurementssolidangle>200msrCountat100kHzonlinepionrejectionof102to103Needtoroidtoblockγ’sandlowenergyπ’sJune24,2005d/uMeasurementsforProton(KentPaschkesimulation)AcoupleweeksofbeamtimewithtoroidspectrometerJune24,2005Example:d/uofProtond/uCompareMADSpectr.toToroidSpectr.offshellonshellCurvesfromMelnithoukandThomasWhatPhysicsisAllowedbyNewDevice?June24,2005EMCeffectinParityViolation?CrosssectiondatafromJ.Gomezet.al.PRD49(1994)4348June24,2005HighxPhysicsOutlook:ContextParity-ViolatingDIScanprobeexcitingnewphysicsathighxOnecanstartnow(at6GeV)Do2lowQ2points(P-05-007,X.Zhengcontact)Q2~1.1and1.9GeV2EitherboundorsetthescaleofhighertwisteffectsTakedataforW<2(P-05-005,P.Bostedcontact)DualityCouldhelpextendrangeat11GeVtohigherxAshortruntoprobeTeVphysicsinPVDISoff2H:HallAorCThebulkoftheprogramrequiresadedicatedspectrometer/detectorCSVcanalsobeprobedviaelectroproductionofpions6GeVbeamcanprobex~0.45(P-05-006,K.Hafidicontact)Shouldbeabletogotohigherxwith12GeVbeamOthervitalphysicstopicscouldbeaddressedbydedicatedspectrometer:Transverse(beam-normal)asymmetriesinDISPolarizedtargets:g2andg3structurefunctionsHighertwiststudiesofA1pandA1nJune24,2005Summary12GeVUpgradeOpensuniqueopportunitiesfornewPVmeasurementsHallconfigurationmustsupportdedicatedapparatusLargesolidangletoroid/calorimeterforPVDISSuperconductingsolenoidforM?llerscatteringPhysicsHighlightsUniqueStandardModeltestsUnique,cleand/uforprotonTestChargeSymmetryattheQuarklevelObservecleanhighertwisteffectsNewprobeforEMCeffect?June24,2005FutureDirectionsforPVMollerandAPVe2ePV:Parity-ViolatingMollerscatteringat12GeVJLAB(Mack,Reimer,etal.)

Parisgroup(Bouchiat,etal.):morepreciseCsAPVSeattlegroup(Fortson,etal.):singletrappedBa+APV6S1/2

5D3/2Berkeleygroup(Budker,etal.):isotoperatiosinYbAPVStonyBrookgroup(Orozco,etal.):isotoperatiosinFrAPVNote:isotoperatioscaneliminatelargeatomicstructuretheoryuncertaintiesAtomicParityViolationFutureDirectionsAchieveMollerfocuswithlong,narrowsuperconductingtoroidalmagnet,RadiationharddetectorpackageE=12GeVQ2=.008GeV2,~.53-.92o,APV=-40ppbIn4000hours,coulddetermineQeWto2.5%(compareto12.4%forE158)June24,2005OverviewoftheQpWeakExperimentIncidentbeamenergy:1.165GeVBeamCurrent:180μABeamPolarization:85%LH2targetpower:2.5KWCentralscatteringangle: 8.4°±3°PhiAcceptance: 53%of2pAverageQ2: 0.030GeV2Acceptanceaveragedasymmetry: –0.29ppmIntegratedRate(allsectors): 6.4GHzIntegratedRate(perdetector): 800MHzExperimentParameters(integrationmode)PolarizedElectronBeam35cmLiquidHydrogenTargetCollimatorwith8openingsθ=8°±2°RegionIGEMDetectorsRegionIIDriftChambersToroidalMagnetRegionIIIDriftChambersElasticallyScatteredElectronEightFusedSilica(quartz)?erenkovDetectorsLuminosityMonitorsJune24,2005“Runningofsin2W〞:CurrentStatusandFutureProspectspresent:“d-quarkdominated〞:CesiumAPV(QAW):SMrunningverifiedat~4level“purelepton〞:SLACE158(QeW):SMrunningverifiedat~6levelfuture:“u-quarkdominated〞:Qweak(QpW):projectedtotestSMrunningat~10level“purelepton〞:12GeVe2ePV(QeW):projectedtotestSMrunningat~25level12GeVQW

(e)June24,2005ComparingQweandQWpErler,Kurylov,R-MQWP=0.0716QWe=0.0449ExperimentSUSYLoopsE6Z/bosonRPVSUSYLeptoquarksSMSMJLabat12GeVwilldoafactorofabout5better!June24,2005TheQweakExperimentJune24,2005NewPhysicsReach

ee~25TeVJLabM?ller

ee~15TeVLEP200LHCComplementary;1-2TeVreachNewContactInteractionsDoesSupersymmetry(SUSY)provideacandidatefordarkmatter?LightestSUSYparticle(neutralino)isstableifbaryon(B)andlepton(L)numbersareconservedHowever,BandLneednotbeconservedin

SUSY,leadingtoneutralinodecay(RPV)Examples:Kurylov,Ra