High-pt-Heavy-Ion-physics：高鉑重離子物理教學(xué)課件

Hotanddensematter:

HardprobesfromRHICtoLHCM.vanLeeuwen,UtrechtUniversityHardprobesofQCDmatterUsethestrengthofpQCDtoexploreQCDmatterUse‘quasi-free’partonsfromhardscatteringstoprobe‘quasi-thermal’QCDmatterInteractionsbetweenpartonandmedium:RadiativeenergylossCollisionalenergylossHadronisation:fragmentationandcoalescenceSensitivetomediumdensity,transportpropertiesCalculablewithpQCDQuasi-thermalmatter:dominatedbysoft(few100MeV)partonsEnergylossinQCDmatterradiatedgluonpropagatingpartonlm2QCDbremsstrahlung

(+LPMcoherenceeffects)Densityofscatteringcenters:Natureofscatteringcenters,e.g.mass:radiativevselasticlossOrnoscatteringcenters,butfields

synchrotronradiation?TransportcoefficientEnergylossEnergylossprobes:RelativisticHeavyIonColliderPHENIXSTARAu+AusNN=200GeVRHIC:varietyofbeams:p+p,d+Au,Au+Au,Cu+CuTwolargeexperiments:STARandPHENIXSmallerexperiments:PHOBOS,BRAHMSdecomissionedRecentyears:Largedatasamples,reachtohighpTEnergylossinQCDmatterD.d’EnterriaHardpartonsloseenergyinthehotmatter:nointeractionsHadrons:energylossRAA=1RAA<1Yieldpercollision0:RAA

≈0.2:RAA=1NuclearmodificationfactorC.Vale,K.Okada,HardProbes2019WhatcanwelearnfromRAA?Thisisacartoon!Hadronic,notpartonicenergylossNoquark-gluondifferenceEnergylossnotprobabilisticP(DE)Ball-parknumbers:DE/E≈0.2,orDE≈2GeV

forcentralcollisionsatRHICp0spectraNuclearmodificationfactorPHENIX,PRD76,051106,arXiv:0801.4020Note:slopeof‘input’spectrumchangeswithpT:useexperimentalreachtoexploitthisEnergydistributionfromtheoryTECHQM‘brickproblem’L=2fm,DE/E=0.2E=10GeV‘TypicalforRHIC’Notanarrowdistribution:SignificantprobabilityforDE~EConceptually/theoreticallydifficultSignificantprobability

tolosenoenergyT.RenkFornuclearcollisions,

needtofoldingeometryASW:Armesto,Salgado,WiedemannWHDG:Wicks,Horowitz,Dordjevic,GyulassyDeterminingthemediumdensityPQM(Loizides,Dainese,Paic),

Multiplesoft-scatteringapprox(Armesto,Salgado,Wiedemann)

RealisticgeometryGLV(Gyulassy,Levai,Vitev),

Opacityexpansion(L/l),

AveragepathlengthWHDG(Wicks,Horowitz,Djordjevic,Gyulassy)

GLV+realisticgeometryZOWW(Zhang,Owens,Wang,Wang)

Medium-enhancedpowercorrections(highertwist)

HardspheregeometryAMY(Arnold,Moore,Yaffe)Finitetemperatureeffectivefieldtheory(HardThermalLoops)Foreachmodel:VaryparameterandpredictRAAMinimize2wrtdataModelshavedifferentbut~equivalentparameters:Transportcoeff.GluondensitydNg/dyTypicalenergylossperL:e0CouplingconstantaSPHENIX,arXiv:0801.1665,

J.NagleWWND08MediumdensityfromRAAPQM<q>=13.2GeV2/fm+2.1-3.2^GLVdNg/dy=1400+270-150WHDGdNg/dy=1400+200-375ZOWWe0=1.9GeV/fm+0.2-0.5AMYas=0.280+0.016-0.012Quantitativeextractiongivesmediumdensityto10-20%

Differentmodelsapproximatelyagree–exceptPQM,highdensityDensity30-50xcoldnuclearmatterMethodextractsmediumdensitygiventhemodel/calculation

Theoryuncertaintiesneedtobefurtherevaluatede.g.comparingdifferentformalisms,varyinggeometryHeavyquarksuppressionPHENIXnucl-ex/0611018,STARnucl-ex/0607012Djordjevic,Phys.Lett.B632,81Armesto,Phys.Lett.B637,362Measuredsuppressionofnon-photonicelectronslargerthanexpectedUsingnon-photonicelectronslightM.Djordjevic

PRL94Wicks,Horowitzetal,NPA784,426ExpectedenergylossExpect:heavyquarksloselessenergyduetodead-coneeffectMostpronouncedforbottomRadiative(+collisional)energylossnotdominant?

E.g.:in-mediumhadronisation/dissociation(vanHees,etal)Di-hadroncorrelationsassociatedtrigger8<pTtrig<15GeVpTassoc>3GeVUsedi-hadroncorrelationstoprobethejet-structureinp+p,d+AuNearsideAwaysideandAu+AuCombinatorial

backgroundd-AuAu-AuMediumdensityfromdi-hadronmeasurementIAAconstraintDAAconstraintDAA+scaleuncertaintyJ.Nagle,WWND2019associatedtriggere0=1.9GeV/fmsinglehadronsMediumdensityfrom

away-sidesuppression

andsinglehadron

suppressionagreeTheory:ZOWW,PRL98,212301However:Theorycurvedoesnotmatchd+Au:needtoevaluatesystematicsExperimentaluncertaintieswilldecreaseinnearfutureData:STARPRL95,1523018<pT,trig<15GeVzT=pT,assoc/pT,trigLoweringpT:gluonfragments/bulkresponse3<pt,trigger<4GeVpt,assoc.>2GeVAu+Au0-10%STARpreliminaryassociatedtriggerJet-likepeak`Ridge’:associatedyieldatlargedN/dapprox.independentofStrong-asymmetrysuggestseffectoflongitudinalfloworunderlyingeventLong.flowLong.flowJ.Putschke,M.vanLeeuwen,etald+Au,200GeVAssociatedyieldsfromcoalescenceBaryon

pT=3pT,partonMeson

pT=2pT,partonExpectlargebaryon/mesonratioassociatedwithhigh-pTtriggerExpectreducedassociatedyieldwithbaryontriggers3<pT<4GeV(Hwa,Yang)HotmatterBaryon

pT=3pT,partonMeson

pT=2pT,partonHardpartonHotmatterRecombinationof

thermal(‘bulk’)partons

‘Shower-thermal’

recombination

Nojetstructure/associatedyieldAssociatedbaryon/mesonratiosBaryon/mesonratioinridgeclosetoAu+Auinclusive,injetclosetop+pDifferentproductionmechanismsforridgeandjet?p+p,d+Au:B/M0.3Au+Au:

BaryonenhancementInclusivespectrapTtrig>4.0GeV/c2.0<pTAssoc

<pTtrig

C.Suarezetal,QM08p+p/p++p-Ridge(largeDh):BaryonenhancementJet(smallDh)B/M0.3AssociatedyieldsPartonenergyfromg-jetandjetreconstructionQualitatively:`known’frome+e-knownpQCDxPDFextractFulldeconvolutionlargeuncertainties(+nottransparent)Fix/measureEjettotakeonefactoroutTwoapproaches:g-jetJetreconstructionsecond-generationmeasurementsatRHICSTARPreliminaryIAA(zT)=DAA

(zT)Dpp

(zT)Direct-grecoilsuppressionLargesuppressionforaway-side:factor3-5ResultsagreewithmodelpredictionsUncertaintiesstillsizable

Someimprovementsexpectedforfinalresults

FutureimprovementswithincreasedRHICluminosityJ.Frantz,HardProbes2019A.Hamed,HardProbes20198<ET,g<16GeVET,g2<pTassoc<10GeVExpectedrecoilforvariousP(DE)T.RenkMeasurementsensitivetoenergylossdistributionP(DE)NeedprecisiontodistinguishscenariosJetreconstructioninheavyioneventsjηptpergridcell[GeV]STARpreliminary~21GeVFastJet:Cacciari,SalamandSoyez;arXiv:0802.1188/~putschke/Ahijf/A_Heavy_Ion_Jet-Finder.htmlJetsclearlyvisiblein

heavyioneventsatRHICQuantitativeanalysisrequires:Goodjet-findingalgorithmCombinatorialbackgroundsubtractionUsedifferentalgorithmstoestimatesystematicuncertainties:Cone-typealgorithms

simplecone,iterativecone,infraredsafeSISConeSequentialrecombinationalgorithms

kT,Cambridge,inversekTJetspectrum–RAAofjetsLOHSCpTcut=1GeVR=0.4Seed=4.6GeVCounts?EE=EPyDet–EPyTrue

E=EPyEmbed-EPyTrue

E=EPyEmbed-EPyDetSTARPreliminaryET=35±5GeVdNJet/dET(perevent)PyDetPyEmbedPyTrueLOHSCseed=4.6GeVR=0.4STARPreliminarypTcut

=1.0GeVEnergyresolutionPythiajet+HeavyionbackgroundEffectofresolutiononspectrumNosignificantsuppressionofjetproductioninAAJetreconstructionrecoversunbiasedjetsampleET[GeV]Nbinscaledp+pAu+Au0-10%

MB-TrigOHT-TrigR=0.4pTcut=1GeVSeed=4.6GeVLOHSCStatisticalErrorsOnlydNJet/dET(perevent)S.Salur,HardProbes2019pthadron~10GeVAu+AuHTEt>7.5GeVp+pHTEt>5.4GeVJetfragmentationpt,jetrec.>30GeVNoapparentmodificationinthefragmentationfunctionwithrespecttop+pJ.Putschke,HardProbes2019FragmentationfunctionFragmentationfunctionratioA+A/p+pJet-energyuncorrected–needsstudySTARpreliminary

stat.errorsonlyRelatingjetsandsinglehadronsHigh-pThadronsfromjetfragmentationQualitatively:Measuredsuppressionofsinglehadrons:Suppressionofjetyield(out-of-coneradiation)Modificationoffragmentdistribution(in-coneradiation)FirstresultsfromSTARshowneitherWorkinprogress:Betterunderstandingofinterplaybetweenreconstructionbiases

(triggerbias,backgroundsubtraction)andjet-quenchingneededRequirestheory-experimentcollaborationNewdevelopment:E-lossgenerators2modelsJEWELK.Zapp,U.Wiedemann,arXiv:0804.3568Focusoncollisionalenergyloss

+mediumresponseClusterhadronisationq-PYTHIAL.Cunqueiro,N.Armesto,C.Salgado,arXiv:0809.4433FocusonradiativeenergylossModifiedshowerevolutionImportantstepforthefieldEventgeneratorstreatfull

in-mediumQCDshower:Theory/modeladvantageoveranalyticapproach:

conserveenergy/respectkinematicboundsImportantexperimentaltool:

canperformjetreconstruction(andotheranalysis)onmodelTransportandmediumpropertiesBroadagreementbetweendifferentobservables,andwiththeorypQCD:2.8±0.3GeV2/fm(Baier)e

23±4GeV/fm3T400MeV

TransportcoefficientTotalETViscosity(modeldependent)t0=0.3-1fm/c~

5-15GeV/fm3

T~250-350MeV

(Bjorken)Fromv2(seeprevioustalk:Steinberg)(Majumder,Muller,Wang)LatticeQCD:h/s<0.1AquantitativeunderstandingofhotQCDmatterisemerging(Meyer)OutlookI:LHCSimulatedresultALICEEMCalTDRForexample:Canmeasure

jetfragmentationwithEjet=175GeVLargehardprocessyields:Jetsto>200GeVLight,heavyhadronsto100GeVUsekinematicreach(DE>>E)to

determineenergydependenceofDETest/validateunderstandinggainedfromRHICTalksbyT.Awes,M.Spousta,L.SarychevaOutlookII:RHICOngoingdataanalysis:LargesampleAu+Au(run-7)andd+Au(run-8)AcceleratorupgradesStochasticcoolingProjectedperformancefor

g-hadronmeasurementDetectorupgradesVertexdetectorsPHENIXSTAREnablescharm/bottomdirectmeasurementsConclusionRHICresults:‘Standard’measurementsextenttohighpT,starttoconstraintheoryindetailIntermediatepT:interplaybetweenhardandsoftphysics,e.g.‘theridge’Newlargesamples:experimentalcontroloverEpartonGamma-jetanalysisJetreconstructionHardprobesprovideinsightinnatureofhotQCDmatterDE~2GeVatRHIC,DE/EnotsmallStartsystematiccomparisonsofdifferentmeasurementswiththeory

AssessmentofsystematicsintheoryandexperimentProgresstowards‘globalanalysis’ofheavyiondataFuture:RHIC:largerluminosity,detectorupgradesLHC:LargeratesathighpT,exploitDE<ETheory:developin-mediumshowergeneratorsConclusionRecentdevelopments:LargeluminosityatRHICExtendtohigherpTGamma-hadronanalysis(fixpartonenergy)JetreconstructionNearfutureatLHCLargeratesathighpT,exploitDE<ETheory:developin-mediumshowergeneratorsHardprobesprovideinsightinnatureofhotQCDmatterDE~2GeVatRHIC,DE/EnotsmallStartcombiningdifferentmeasurementstoimproveunderstanding-AssessmentofsystematicsintheoryandexperimentProgresstowards‘globalanalysis’ofheavyiondataExtraSlidesDirect-grecoilyieldsA.Hamed,HardProbes2019Run4p+p/Au+Au200GeVM.Nguyen,QuarkMatter2019Direct-g–jetmeasurementsbeingpursuedbySTARandPHENIXRequireslargedatasamplesSuppressionofaway-sideyieldvisibleSimilartodi-hadrons,butnowwithselectedpartonenergyAway-sidesuppressionA.HamedetalQM08Firstg-jetresultsfromheavyioncollisionsMeasuredsuppressionagreeswiththeoryexpectationsNextstep:measurepTassocdependencetoprobeDEdistributionModelpredictions

tunedtohadronic

measurementsAway-sideyieldAuAu/pp3<pt,trig<4GeV/cAu+Au0-10%STARpreliminaryassociatedtrigger`Ridge’:associatedyieldatlarge,smallDfStrong-asymmetrysuggestscouplingtolongitudinalflowJ.Putschkeetal,QM06WeakdependenceofridgeyieldonpT,trigRelativecontributionreduceswithpT,trig4<pt,trig<6GeV/cAu+Au0-10%STARpreliminaryJet-likepeakpt,assoc.>2GeV/cIntermediatepT:theridgeRAAatLHCS.Wicks,W.Horowitz,QM2019T.Renk,QM2019ExpectedriseofRAAwithpTdependsonenergylossformalismNuclearmodificationfactorRAAatLHCsensitivetoradiationspectrumP(E)LHC:typicalpartonenergy>typicalEGLVBDMPSRHICRHICAnti-Baryon/mesonratioBaryon/mesonratiosTheory:X.-N.Wang,PRC70,031901Largebaryon/mesonratioatintermediatepTHadronisationbycoalescenceofquarks?P.Fachinietal,QM08NewdataextendpT-rangeinp+pp/pratioExpectpmainlyfromgluonsandDEg>DEq,

nostrongersuppressionseenforpNewSTARresultsonbaryonfragmentationinp+p,seeM.HeinzHeavy-lightdifferenceExpect:dead-coneeffectArmestoplotArmestoetal,PRD71,054027Below10GeV:charmloses20-30%lessenergythanu,dBottomloses~80%lessExpectedsuppressionofDmesons~0.5timeslighthadronslightM.Djordjevic

PRL94(2019)Wicks,Horowitzetal,NPA784,426Heavyflavour:DiscrepancySTAR/PHENIXspectraPHENIX:A/(exp(-apT-bpT2)+pT/p0)n:A=377+/-60mbGeV^-2c^3a=0.3565+/-0.014c/GeV

b=0.0680+/-0.019(c/GeV)^2p0=0.70+/-0.02(c/GeV)

n=8.25+/-0.0435ZhangbuXu(STARCollaboration)SQM08e/pratioConversionind