J/J/ee++ee-- Measurement Measurementin Cu+Cu Collisionsin Cu+Cu Collisions

at RHIC-PHENIXat RHIC-PHENIXSusumu OdaSusumu Oda

CNS, University of TokyoCNS, University of Tokyofor the PHENIX Collaborationfor the PHENIX CollaborationMarch 27th 2006 (Monday)March 27th 2006 (Monday)

61st Annual Meeting of the Physical Society of Japan61st Annual Meeting of the Physical Society of JapanEhime UniversityEhime University

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1. Physics Motivation1. Physics Motivation

Yields of heavy quarkonia are expected to be suppressed Yields of heavy quarkonia are expected to be suppressed via color screening.via color screening. Measurement of quarkonia is one of the most promising probMeasurement of quarkonia is one of the most promising prob

es for a hot and dense matter created in heavy ion collisions.es for a hot and dense matter created in heavy ion collisions. However, other competing effects influence quarkonia yieldHowever, other competing effects influence quarkonia yield

s.s. Cold matter effects (shadowing, nuclear absorption)Cold matter effects (shadowing, nuclear absorption) Recombination Recombination

Therefore, systematic study of quarkonia production is impTherefore, systematic study of quarkonia production is important.ortant. Nuclear species : p+p, d+Au, Nuclear species : p+p, d+Au, Cu+CuCu+Cu and Au+Au and Au+Au Collision energy : 62.4 GeV and 200 GeVCollision energy : 62.4 GeV and 200 GeV

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2. PHENIX Experiment2. PHENIX Experiment Beam Beam CounterBeam Beam Counter

Minimum bias triggerMinimum bias trigger Collision vertex Collision vertex CentralityCentrality

Drift Chamber and Pad CDrift Chamber and Pad Chamberhamber

MomentumMomentum Ring Imaging CherenkovRing Imaging Cherenkov

Electron IDElectron ID Electron triggerElectron trigger

EM CalorimeterEM Calorimeter EnergyEnergy Track matchingTrack matching Electron triggerElectron trigger

Muon TrackerMuon Tracker Muon IdentifierMuon Identifier

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3. Invariant mass plot3. Invariant mass plotdi-electron channeldi-electron channel

J/J/ mass : 3.097 GeV/c mass : 3.097 GeV/c22 J/J/ee++ee-- : BR 5.93 +/- 0.10 % : BR 5.93 +/- 0.10 %J/J/++-- : BR 5.88 +/- 0.10 % : BR 5.88 +/- 0.10 %

Cu+Cu 200GeV700 J/’s

Cu+Cu 62.4GeV

Full data production finished last week.Full data production finished last week.Level-2 filtered dataLevel-2 filtered dataFull data production will start soon.Full data production will start soon.

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Cu+Cu 62.4GeV40 J/’s

Cu+Cu 200GeV : Jan. – Mar. 2005Cu+Cu 200GeV : Jan. – Mar. 2005Cu+Cu 62.4GeV : March 2005Cu+Cu 62.4GeV : March 2005

4-1. Nuclear 4-1. Nuclear modification factor Rmodification factor RABAB

There is strong suppression bThere is strong suppression beyond cold matter effects in ceyond cold matter effects in central Cu+Cu and Au+Au collientral Cu+Cu and Au+Au collisions.sions.

|y|<0.35ee

1.2<|y|<2.4

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deuterondeuteron goldgoldPRL 96, 012304 (2006) PRL 96, 012304 (2006)

4-1. Nuclear modification factor R4-1. Nuclear modification factor RAA AA

　　Models that were successful in Models that were successful in describing SPS data fail to describing SPS data fail to describe data at RHIC.describe data at RHIC.

Recombination models agree Recombination models agree with data much better.with data much better.

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4-2. pT distribution4-2. pT distribution <p<pTT

22> > was extracted by was extracted by fittingfitting with with A(1+(pA(1+(pTT/B)/B)22))-6-6

Data seems to favor model Data seems to favor model with recombination.with recombination.

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R.L. Thews et al.R.L. Thews et al.

2

without recombination

with recombination

　　 Cu+Cu 200GeVCu+Cu 200GeV 　　　　

4-3. Rapidity 4-3. Rapidity distributiondistribution

Recombination models expect rapidity Recombination models expect rapidity shape to become narrower for increasshape to become narrower for increasing Npart.ing Npart.

No significant change in rapidity shapNo significant change in rapidity shape with centrality.e with centrality. R.L. Thews and M.L. ManganoR.L. Thews and M.L. Mangano

Phys.Rev. C73 (2006) 014904 Phys.Rev. C73 (2006) 014904

　　 Cu+Cu 200GeVCu+Cu 200GeV 　　　　 　　 Au+Au 200GeVAu+Au 200GeV 　　　　

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PHENIX Preliminary

5. Summary5. Summary

PHENIX measured J/PHENIX measured J/di-lepton in Cu+Cu, Audi-lepton in Cu+Cu, Au+Au, d+Au and p+p collisions.+Au, d+Au and p+p collisions.

Strong suppression beyond cold matter effects is Strong suppression beyond cold matter effects is obserbed.obserbed.

Models that were successful in describing SPS dModels that were successful in describing SPS data fail to describe data at RHIC.ata fail to describe data at RHIC.

Recombination agrees with observed suppressiRecombination agrees with observed suppression pattern and pT distribution.on pattern and pT distribution.

However, expected rapidity shape change is not However, expected rapidity shape change is not observed.observed.

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6. Outlook6. Outlook Proceed analysis and publish less systematic error result.Proceed analysis and publish less systematic error result.

Other observablesOther observables J/J/ polarization polarization J/J/ hadron correlation hadron correlation Elliptic flow of J/Elliptic flow of J/

• Reaction plane detectorReaction plane detector

Other heavy quarkoniaOther heavy quarkonia Feed down effectFeed down effect

• ’’J/J/ + anything (BR 58%) + anything (BR 58%)• ccJ/J/ (BR 32%, 20%) (BR 32%, 20%)

Different dissociation temperatureDifferent dissociation temperature• TT’<T’<Tcc<TJ/<TJ/

Bottomonium : Bottomonium : RHIC-II : luminosity upgradeRHIC-II : luminosity upgrade

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T.Frawley Heavy Flavor Productions and Hot/Dense Quark Matter Dec. 2005