1. Workshop on QCD and RHIC Physics, Hefei, July 9-121 Heavy Flavors in High Energy Nuclear Collisions ZHUANG Pengfei (Tsinghua University, Beijing) ● J/Psi Suppression and Regeneration ● J/Psi Suppression and Regeneration ● D Meson Correlation and Collective Flow ● D Meson Correlation and Collective Flow I thank Jorg Hufner (Heidelberg), XU Nu (LBNL) and YAN Li, ZHU Xianglei (Tsinghua) I thank Jorg Hufner (Heidelberg), XU Nu (LBNL) and YAN Li, ZHU Xianglei (Tsinghua)

2. Workshop on QCD and RHIC Physics, Hefei, July 9-122 ● heavy quarks are produced only in the initial impact, and no extra production in the later evolution a probe of early thermalization and a probe of QGP ● production via pQCD process rather solid ground importance of heavy quarks B.Mueller, nucl-th/0404015

3. Workshop on QCD and RHIC Physics, Hefei, July 9-123 ● both initial production and regeneration ● both normal suppression and anomalous suppression J/Psi motion in heavy ion collisions Matsui and Satz PLB178, 416(1986): J/Psi suppression as a signature of QGP formation in HI

4. Workshop on QCD and RHIC Physics, Hefei, July 9-124 normal suppression mechanism: multi-scattering between J/psi and spectator nucleons mechanism: multi-scattering between J/psi and spectator nucleons R.Vogt, Phys.Rept.310, 197(1999) R.Vogt, Phys.Rept.310, 197(1999) C.Gerschel, J.Hufner, Annu.Rev.Nucl.Part.Sci. 49, 225(1999) C.Gerschel, J.Hufner, Annu.Rev.Nucl.Part.Sci. 49, 225(1999) conclusion: nuclear absorption can well explain the J/psi yield in p-A and light nuclear collisions at SPS energy ! NA38

5. Workshop on QCD and RHIC Physics, Hefei, July 9-125 anomalous suppression I anomalous suppression in heavy ion collisions model 1: Debye screening (Matsui & Satz, 1986) NA38 Kaczmarek et al., hep-lat/0312015 charmonium dissociation temperature (Karsch, Kharzeev, Satz, PLB637, 75(2006) charmonium dissociation temperature (Karsch, Kharzeev, Satz, PLB637, 75(2006) at T=0 at T≠ 0 Asakawa & Hatsuda, 2004

6. Workshop on QCD and RHIC Physics, Hefei, July 9-126 anomalous suppression II model 3: comover interaction (Capella, Feireiro, Kaidalov, PRL85, 2080(2000) model 2: threshold model (Blaizot, Dinh, Ollitrault, PRL85, 4010(2000) dynamic processes:

7. Workshop on QCD and RHIC Physics, Hefei, July 9-127 regeneration I there are about 10 pairs of c quarks in a central Au-Au collision at RHIC energy and more than 100 pairs at LHC energy very important J/\psi regeneration at high energies: in QGP in QGP in hadron gas in hadron gas the competition between J/\psi suppression and regeneration leads to the question: J/\psi suppression or enhancement at high energies? model 1: sudden production (Andronic, PBM, Redlich, Stachel, NPA789, 334(2007): J/\psi’s are statistically produced at T=Tc, no initial production mesons suppression at RHIC, no clear enhancement at LHC suppression at RHIC, no clear enhancement at LHC

8. Workshop on QCD and RHIC Physics, Hefei, July 9-128 regeneration II model 2: continuous production in QGP (Thews, Mangano, PRC73, 014904(2006): J/\psi’s are continuously produced in the whole QGP region including anomalous suppression no initial production * perturbative calculation with nonrelativistic Coulomb potential (Peskin, Bhanot, NPB156, 365(1979) * detailed balance model 3: two-component model (Grandchamp, Rapp, Brown, PRL92, 212301(2004): initial production + sudden regeneration the yield in central collisions is controlled by the regeneration ! the yield in central collisions is controlled by the regeneration !

9. Workshop on QCD and RHIC Physics, Hefei, July 9-129 necessary regeneration ? heavy quark potential (Young, Shuryak, 2008): heavy quark potential (Young, Shuryak, 2008): V = U, F=U-TS V = U, F=U-TS Schroedinger equation: J/psi dissociation temperature Td = 2.7 Tc > maximum T at RHIC. Schroedinger equation: J/psi dissociation temperature Td = 2.7 Tc > maximum T at RHIC. there is no big difference between SPS and RHIC ! This explains why there is no big difference between suppressions at SPS and at RHIC. there is no big difference between SPS and RHIC ! This explains why there is no big difference between suppressions at SPS and at RHIC. regeneration looks not necessary !? regeneration looks not necessary !?

10. Workshop on QCD and RHIC Physics, Hefei, July 9-1210 transport model (Hufner and Zhuang, PLB559, 193(2003): transport equation for J/\psi and hydrodynamics for QGP leakage for J/\psi yield, almost all the models – with and without the assumption of QGP and with and without regeneration mechanism – describe the observed suppression, after at least one parameter is adjusted. the transverse momentum distribution which depends more directly on the production mechanism may contain additional information about the nature of the medium and J/\psi and may help to distinguish between different scenarios. the transverse momentum distribution which depends more directly on the production mechanism may contain additional information about the nature of the medium and J/\psi and may help to distinguish between different scenarios. transverse momentum I anomalous suppression regeneration comover mechanism no regeneration at SPS very important leakage effect ! direct production & nuclear absorption as initial condition

11. Workshop on QCD and RHIC Physics, Hefei, July 9-1211 general solution of the transport equation at RHIC and LHC: transverse momentum II Yan, Xu, Zhuang, PRL97, 232301(2006)

12. Workshop on QCD and RHIC Physics, Hefei, July 9-1212 dominant regeneration at LHC rapidity dependence, a possible evidence of regeneration at RHIC ! PHENIX, PRL98, 232301(2007) Liu, Xu, Zhuang: the calculation in transport model is in progress while both initial production and regeneration are important at RHIC, the J/psi yield at LHC is characterized by the regeneration only! * enhanced R_AA at LHC * large V2 at LHC

13. Workshop on QCD and RHIC Physics, Hefei, July 9-1213 near side correlation at LHC we take drag coefficient to be a parameter charactering the coupling strength * c quark motion in QGP: * QGP evolution: ideal hydrodynamics for strongly interacting quark-gluon plasma: ● at RHIC, the back-to-back correlation is washed out. ● at LHC, c quarks are fast thermalized, the strong flow push the D and Dbar to the near side! Zhu, Xu, Zhuang, PRL100, 152301(2008) large drag parameter is confirmed by R_AA and v_2 of non-photonic electrons (PHENEX, 2007; Moore and Teaney, 2005; Horowitz, Gyulassy, 2007).

14. Workshop on QCD and RHIC Physics, Hefei, July 9-1214 heavy quark thermolization ● only charm quarks (D mesons) with pt<2 GeV are thermalized ● averaged thermalization time is about 3 fm/c ● only charm quarks (D mesons) with pt<2 GeV are thermalized ● averaged thermalization time is about 3 fm/c Greco, Ko, Rapp, 2004

15. Workshop on QCD and RHIC Physics, Hefei, July 9-1215 ● J/Psi RHIC: both initial production and regeneration RHIC: both initial production and regeneration J/\psi suppression and small V2 J/\psi suppression and small V2 LHC: only regeneration LHC: only regeneration J/\psi enhancement and large V2 J/\psi enhancement and large V2 FAIR: only initial production FAIR: only initial production very small V2 very small V2 the calculation at RHIC needs a quite accurate fine-tuning between the initial production and regeneration, but the case at LHC (only regeneration) or FAIR (only initial production) is quite clean. the calculation at RHIC needs a quite accurate fine-tuning between the initial production and regeneration, but the case at LHC (only regeneration) or FAIR (only initial production) is quite clean. conclusions ● DDbar correlation, a signal sensitive to sQGP RHIC: back-to-back correlation disappears RHIC: back-to-back correlation disappears LHC: near side correlation LHC: near side correlation ● charm quark thermalization only charm quarks with pt<2 GeV are thermalized only charm quarks with pt<2 GeV are thermalized averaged thermalization time is about 3 fm/c averaged thermalization time is about 3 fm/c

16. Workshop on QCD and RHIC Physics, Hefei, July 9-1216 ● medium effect on charm quark and on charmonium strongly coupled QGP, chiral symmetry restoration, critical behavior, strongly coupled QGP, chiral symmetry restoration, critical behavior, mass, width, binding energy,...... mass, width, binding energy,...... see Lee, arXiv:08050471 see Lee, arXiv:08050471 ● cold nuclear matter effect (initial parton rescattering) see Qiu, Vary, Zhang, PRL88, 232301(2002) see Qiu, Vary, Zhang, PRL88, 232301(2002) outlook ● charm quark production in QGP see Xu, NPA697, 825(2002), Ko, this workshop see Xu, NPA697, 825(2002), Ko, this workshop ● charm quark potential between free energy F=U-TS and internal energy between free energy F=U-TS and internal energy different dissociation temperature (from Schroedinger equation) different dissociation temperature (from Schroedinger equation) see Young, Shuryak, arXiv:0803.2866 see Young, Shuryak, arXiv:0803.2866

17. Workshop on QCD and RHIC Physics, Hefei, July 9-1217