從雙輕子產(chǎn)生探測致密物質(zhì)狀態(tài)方程

1、Di-lepton production as probe Di-lepton production as probe to dense matter EOSto dense matter EOS從雙輕子產(chǎn)生探測致密物質(zhì)狀態(tài)方程從雙輕子產(chǎn)生探測致密物質(zhì)狀態(tài)方程Jian Deng (鄧建)Department of modern physics, USTCwith Q. Wang, N. Xu, P.-f Zhuang2009-11-7USTC第十三屆中高能核物理大會Background and Motivation Background and Motivation Hydrodynamics

2、 for HICHydrodynamics for HICDi-lepton spectra after evolutionDi-lepton spectra after evolutionSensitivity to EOS Sensitivity to EOS Summary and conclusionSummary and conclusionBackgroundDense or hot QCD matterProperty? Transition? Electromagnetic Electromagnetic probe for probe for early universeea

3、rly universe 1. Chiral symmetry1. Chiral symmetryrestorationrestoration2. Electromagnetic2. Electromagneticprobe to hot/denseprobe to hot/densemediummedium3. Space-time 3. Space-time evolution of fireballevolution of fireballDi-lepton invariant mass spectraDi-lepton invariant mass spectraSlope param

4、eter T-eff (MeV)The transition to a low-flow The transition to a low-flow region may signal a transition region may signal a transition from a hadronic source to from a hadronic source to a partonic sourcea partonic sourceNA60, PRL100, 022302(2008)NA60, PRL100, 022302(2008)Effective temperatureHeavy

5、 Ion Collisions HICPCM & clust. hadronizationNFDNFD & hadronic TMPCM & hadronic TMCYM & LGTstring & hadronic TMS. BassHadronization and Freeze-outInitial conditionsInitial condition in high-energy nuclear collisions - Color Glass CondensationCold-QCD-matter, small-x, high-parton

6、density- parton structures in nucleon / nucleusPartonic matter - QGP- The hot-QCDInitial high Q2 interactionsHard scattering production - QCD predictionInteractions with medium - deconfinement/thermalizationInitial parton densityBy Richard. Heeks;From: Hydrodynamics Description Assuming (thermalizat

7、ion, Ideal? Viscous?) Input (EOS, initial condition, Freeze-out criteria) Output (space-time evolution) Comparing with exp. (T_f, v, v2 ) Following (fluctuation, correlation, new statistic )References: References: Baym 86, Rischke 98, Kolb & Heinz, 00, many others . Baym 86, Rischke 98, Kolb &am

8、p; Heinz, 00, many others . Basic for hydrodynamics Local conservation of net charge and energy-momentum 4+1 equations, to solve 10+4 functionsIdeal Hydrodynamics + EOSIdeal Hydrodynamics + EOS For ideal gas in equilibrium 4+1 equations, 5+1 unknown functions +EOS EOS as an input to define the relat

9、ion between energy density, pressure and temperatureScaling and Initialization Scaling and Initialization Landau Model vs Bjorken Model Glauber Model vs CGCBjorken ModelFreeze-out and rapidity platform Cooper-Frye formula Rapidity independenceElliptic flow25-30%P. &U.RomatschkePRL 07Ideal VS Vis

10、cousIdeal VS ViscousDi-lepton production in HIC Drell-Yan process at pre-equilibrium Charmonium and open charm Thermal quark anti-quark annihilation at QGP Thermal pion annihilation at hadronic phase Vector mesons, Dalitz decay, 4-pion processDi-lepton emitted in the fireball, not from the surfaceHo

11、w to calculate Emission radiation in thermal bath:Massless free QGPHadron gasMix phaseLatticeEquation Of StateFree QGPLatticeYield as function of proper timeEOS dependence of yieldFree QGPHadron gasMix phaseLatticeInvariant mass distributionFree QGPHadron gasMix phaseLatticeTwo stage of evolution.M1

12、 GeV: QGP.Slope parameter reflects the temperature and velocity of the thermal source P_T slope: Effective temperatureEOS dependence of slope parameterFree QGPHadron gasMix phaseLatticeEffect from T_c shift Lower Tc, smaller RHG contribution, faster velocity at outer coronal; Less effect to QGP emis

13、sion; Tc 180-150 makes the decline more distinguishable Tc=150 MevTc=180 MevEffect from initial condition shifttau_0=0.6 fm,T_0=350Mevtau_0=0.2 fm,T_0=520Mev No significant difference, except: low effective temperature with cooler initial condition more obvious decline if initialize later EOS depend

14、ence of v2(M,PT)Free QGPHadron gasMix phaseLatticeEOS dependence of v2(M)Free QGPHadron gasMix phaseLatticeIf emission from surfaceIf emission from surfaceNo structure to manifest the phase transitionSummary and Conclusion Ideal Hydrodynamics is used to describe the space-time evolution of HIC. Different di-lepton emission process in QGP and RHG are considered. Di-lepton spectra from different EOS ha