Search for Quark-Gluon Plasma at RHIC对于夸克胶子等离子体在RHIC搜索

1、Byungsik HongKorea UniversityMay 6, 2004Hanyang University2Relativistic Heavy-Ion CollisionsSome of beam energy they had before is transformed into heat and new particles right here ! Approachingv 0.9cCollisionsPassingthroughExpansionMay 6, 2004Hanyang University3Nuclear Phase DiagramT(MeV)Density(n

2、0)15010Early Universe(RHIC)Color SuperconductorNeutron StarHadron GasQuark-Gluon PlasmaPhase TransitionAtomic NucleiSIS explores higSIS explores high baryon density h baryon density hadronichadronic matter. matter.RHIC & future LHRHIC & future LHC explore high teC explore high temperature &a

3、mp; low bmperature & low baryon density partaryon density partoniconic matter. matter.May 6, 2004Hanyang University4Relativistic Heavy-Ion AcceleratorsSIS300SIS300(GSI, Germany)(GSI, Germany)8A8AJust approved; Plan to run from 2010AcceleratorAcceleratorc.m. Energy c.m. Energy (GeV(GeV) )StatusSt

4、atusSIS18SIS18(GSI, Germany)(GSI, Germany)2A2A(A=mass number)(A=mass number)RunningAGSAGS(BNL, USA)(BNL, USA)5A5AFinishedSPSSPS(CERN, Switzerland)(CERN, Switzerland)20A20AFinish soonRHICRHIC(BNL, USA)(BNL, USA)200A200ARunning since 2000LHCLHC(CERN, Switzerland)(CERN, Switzerland)5500A5500APlan to ru

5、n from 2007May 6, 2004Hanyang University5Relativistic Heavy Ion ColliderCircumference: 3.83 km First collision: 2000 100A GeV Au+Au(2X1026/cm2/s) 250 GeV p + p (2X1032/cm2/s)May 6, 2004Hanyang University6PHENIX= Pioneering High Energy Nuclear Interaction eXperimentMay 6, 2004Hanyang University7The S

6、TAR DetectorSTAR=Solenoid Tracker at RHICMay 6, 2004Hanyang University8Outline1. Collective flow2. HBT3. High pt hadron suppression Jet quenchingSummary of the Quark Matter 04 Conference3D imaging of the hot fireball3D imaging of the hot fireballSee more deep insideSee more deep insideMay 6, 2004Han

7、yang University9Collective Flowtimetimereaction planereaction planetransverse planetransverse plane(at (at midrapiditymidrapidity) )v v2 20 v0 0 elliptic flowelliptic flowR RN N=(1+ v=(1+ v2 2)/(1-v)/(1-v2 2) )v v1 10 v0 0sideward flowsideward flowp px x = v = v1 1 p pt t S. Voloshin & Y. Zhang,

8、 Z. Phys. C70, 665 (1996)J.Y. Ollitrault, Nucl. Phys. A638, 195c (1998)Fourier expansion of azimuthalFourier expansion of azimuthal d distribution gives the phase spacistribution gives the phase space distribution w.r.t. the reaction e distribution w.r.t. the reaction plane.plane.)2cos(v2)cos(v21 (2

9、13dyddppNdttRmeasReaction planeReaction planeMay 6, 2004Hanyang University10Anisotropic Flowv1, v2, v4, SpectatorsReaction planeh-3h3h0v2 = 15%v2 = 15%, v4=4%v2 = 7%v2 = 7%, v1=+7%v2 = 7%v2 = 7%, v1=-7%Isotropic emissionSpectatorsXY1In-planeOut-of-plane1.50.50 03 3-3-3xzMay 6, 2004Hanyang University

10、11Directed Flow v1STAR, PRL92, 062301 (2004) NA49, PRC69, 034903 (2003)M. Belt-Tonjes for PHOBOS (QM04)H. Masui for PHENIX (QM04)1. Consistent among RHIC Expts.2. Shape in forward rapidity agree with low energy data by NA493. Elongated shape near midrapidityMay 6, 2004Hanyang University12v2 vs Rapid

11、ityM.B. Tonjes for PHOBOS (QM04)v2 is positive:v1 and v2 are in the same planeSTARSTARMay 6, 2004Hanyang University13v2 vs pt including strangenessSTAR Preliminary D. Molnar and S.A. Voloshin D. Molnar and S.A. Voloshin, PRL 91, 092301(2003), PRL 91, 092301(2003)This saturation can be explained This

12、 saturation can be explained by the surface emission due to tby the surface emission due to the dense & opaque medium,he dense & opaque medium,ShuryakShuryak, PRC 66, 027902 (2002), PRC 66, 027902 (2002)STAR, PRL92, 052302 (2004)May 6, 2004Hanyang University14qoutqsideqlongRsideRlongRout12pp

13、qp1p2q12pp21kHBT interferometryx1x2 Two-particle interferometryTwo-particle interferometry: p-space separation : p-space separation space-time separation space-time separationpairsevent mixedpairsevent real)(P)(P),(P),(212121ppppppC2long2long2side2side2out2out)(1),(RqRqRqekkqCR1Final-state effects (

14、Coulomb, strong) also needto be accounted for.Gaussian model (3-d):May 6, 2004Hanyang University15STAR, PRL 87, 082301 (2001)HBT Excitation Function of kT-dependenceAgree among RHIC expts. May 6, 2004Hanyang University16Azimuthally Sensitive HBT Probes spatial anisotropy at freeze-outWiedemannWiedem

15、ann, PRC57, 266 (1998), PRC57, 266 (1998) Freeze-out shape probes nature & timescale of system evolution How much initial spatial deformation survives system expansion?late rescatteringhydrodynamic expansiontimebeam into screenInitial geometry aniosotropies in pressure gradientsPreferential in-p

16、lane expansion decreases spatial anisotropyFreeze-out source shape model dependent measure of pressure, expansion timeMay 6, 2004Hanyang University17Azimuthally sensitive HBTRside2reactionplaneqoutqsideqlong = 0 = 90Rside (large)Rside (small)May 6, 2004Hanyang University18HBT(): Centrality & kT

17、dependenceSTAR, nucl-ex/0312009Au+Au, s = 200 GeVMay 6, 2004Hanyang University19 Final state eccentricity from v2 HBT with respect to the reaction planeSystem deformation at Freeze-out2222xyxyb t May 6, 2004Hanyang University20Nuclear Modifications to Hard ScatteringRAA(pT) d2NAA/dpTdhTAAd2NN/dpTdh1

18、.Large Cronin effect at low energy2.Large suppression at RHIC (jet quenching)3.Is the suppression due to the medium (Initial or final state effect)?qqPHENIX, PRL91, 072301 (2003); 88, 022031 (2002)May 6, 2004Hanyang University21d+Au Control ExperimentCollisions of small with large nuclei were always

19、 foreseen as necessary to quantify cold nuclear matter effects.Recent theoretical work on the “Color Glass Condensate” model provides alternative explanation of data: Jets are not quenched, but are a priori made in fewer numbers. Kharzeev, Levin, & Nardi, NPA730, 448 (2004)Small + Large distingu

20、ishes all initial and final state effects.Nucleus-nucleuscollisionProton/deuteron-nucleus collisionVSVSMay 6, 2004Hanyang University22RAA vs RdA for Identified p0d+AuAu+AuInitial State Effects OnlyInitial + Final State Effects May 6, 2004Hanyang University23Charged Hadron ResultsStriking difference

21、of d+Au and Au+Au results.Charged Hadrons higher than neutral pions.Cronin Effect:Multiple Collisions broaden high PT spectrumMay 6, 2004Hanyang University24Centrality DependenceDramatically different and opposite centrality evolution of Au+Au experiment from d+Au control one.Jet Suppression is clea

22、rly a final state effect. Au + Au Experimentd + Au Control ExperimentPHENIX, PRL91, 072303 (2003)Preliminary DataFinal DataMay 6, 2004Hanyang University25Rcp VariableThis suppression can be explained This suppression can be explained by the partonby the parton energy loss due to th energy loss due t

23、o the dense & opaque medium,e dense & opaque medium,GyulassyGyulassy & Wang, NPB 420, 583 (1 & Wang, NPB 420, 583 (1994)994)STAR, PRL92, 052303 (2004)May 6, 2004Hanyang University26Jet Quenching;Azimuthal dependence2-Particle Correlations: dN/d() STAR, PRL90, 082302 (2003)trigger“Tri

24、gger” = 0near-sideaway-sideMay 6, 2004Hanyang University27Disappearance of the Away-Side Jetdi-hadron1/NtriggerdN/d()STAR, PRL91, 072304 (2003); 90, 082302 (2003)Background subtractedNear side jet “identical”ppdAuAuAup+p: 2 jetsd+Au: 2 jetsAu+Au peripheral2 jetsAu+Au central1 jet !May 6, 2004Hanyang University28Suppression is larger in out-of-plane (longer path length) !Path Length Dependencedi-hadron, 20 - 60% centralSTAR Preliminarys=200 GeVNNMeasuredReflectedIn-planeOut-of-planeMay 6, 2004Hanyang University292.54 GeV/c12.5 GeV/ctrigTassocTppPath Length Dependencedi-hadron, 20-