Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, J/ J/ Suppression and Regeneration in Quark-Gluon Plasma Pengfei ZHUANG ( ) Tsinghua University, Beijing ( ) 1. Motivation and Our Idea 2. J/ Transport in QGP 3. Comparison with RHIC Data 4. Summary with Li YAN ( ), Xianglei ZHU( ) of Tsinghua and Nu XU ( ) of LBNL nucl-th/ (PRL, accepted) PLB607,107(2005) Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, Motivation J/ suppression: At SPS: At RHIC and LHC: Some Models: Questions: what is the ratio of regenerated to initially produced J/ s ? how to differentiate J/ regeneration mechanisms ? J/ suppression: proposed as a smoking gun for detecting QGP (Matsui and Satz) At SPS: initial production, almost no regeneration, nuclear absorption and suppression in QGP or hadron gas (many works) At RHIC and LHC: regeneration (Thews, Braun-Munzinger, Stachel,, ) supported by lattice calculation of spectral function (Karsch, Hatsuda, ) Some Models: statistic production at hadronization (Braun-Munzinger, Stachel, Gorenstein, Kostyuk, Stoecker, Greiner, Grandchamp, Rapp,), coalescence at hadronization (Greco, Ko, Rapp,), kinetic formation inside QGP (Thews, Mangano, Grandchamp, Rapp, Brown, Polleri, Renk, Schneider, Weise, ) Questions: what is the ratio of regenerated to initially produced J/ s ? how to differentiate J/ regeneration mechanisms ? Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, our treatment both initial production and continuous regeneration in QGP suppression and regeneration via gluon dissociation and the inverse process transport equation for J/ + hydrodynamic equation for QGP two limits for charm quark distribution: no interaction limit and thermalization limit 1. Motivation Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, initial condition: : continuous regeneration in QGP : suppression in QGP 2. J/ Transport in QGP transverse transport equation with loss and gain terms in central rapidity region: p_t broadening due to Cronin effect distribution function: assumption: 40% of final state J/s is from the feed-down of analytic solution first term: initial production, second term: continuous regeneration, both suffer suppression in QGP Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, J/ Transport in QGP loss and gain terms via gluon dissociation thermal gluon distribution controlled by hydrodynamics two limits of charm quark distribution: weak interaction limit, strong interaction limit, suppression and regeneration in hadron gas are neglected, since the hadron density is much lower than the gluon density perturbative calculation with nonrelativistic Coulomb potential (Peskin, Bhanot ) pQCD distribution (Thews,) nuclear geometry thermal distribution controlled by hydrodynamics via detailed balance Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, 1+2 dimensional ideal hydrodynamics of QGP EoS (Sollfrank,) ideal QGP phase: u, d, s (150 MeV) quarks and gluons, ideal hadron phase: hadrons and resonances with mass up to 2 GeV, a first order deconfinement phase transition Initial condition: are determined by (Kolb, Heinz, Rapp,) Parameters at RHIC energy 2. J/ Transport in QGP in thermal distributions Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, Comparison with RHIC Data initial production and regeneration are equally important in central collisions, initial production dominates the yield in semi-central collisions, not sensitive to the charm quark distribution. see also Rapp, Grandchamp, Brown, 2004, 2005 we can not describe the flat structure at in present calculation. PHENIX data nucl-ex/ hep-ex/ yield Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, regeneration is definitely important in central collisions, thermal scenario looks better to fit the data. transverse momentum 3. Comparison with RHIC Data PHENIX data nucl-ex/ hep-ex/ Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, ) initial V2 is small, V2 at SPS is really very small, see Gianluca Usai, this conference 2) regenerated V2 is large 3) total V2 is small due to dominance of initial production V2 can differentiate initial production from regeneration, V2 can answer the question if charm quarks are thermalized, V2 can differentiate sudden from continuous regeneration *V2 can differentiate initial production from regeneration, *V2 can answer the question if charm quarks are thermalized, *V2 can differentiate sudden from continuous regeneration V2 at b=7.8 fm 3. Comparison with RHIC Data Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, ratio of regenerated to initially produced J/s at LHC initially produced charmoniums are all eaten up by QGP, the regeneration dominates the charmonium behavior at any centrality, at LHC are all controlled by the regeneration V2 can differentiate sudden regeneration from continuous regeneration V2 can differentiate sudden regeneration from continuous regeneration 3. Comparison with RHIC Data Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, a J/ transport equation with both initial production and continuous regeneration transverse momentum distributions, especially V2, are sensitive to the production mechanisms at RHIC: significant regeneration in central collisions still important initial production in non-central collisions V2 can differentiate initial production from regeneration at LHC: initially produced J/are eaten up by QGP, and any J/ behavior is dominated by the regeneration. V2 can differentiate sudden from continuous regeneration 4. Summary We thank R.Rapp. H.Stocker, R.Thews and R.Vogt for helpful discussions Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, Charm Quark Thermalazation Question: Are charm quarks thermalized in QGP? Idea: D mesons should be sensitive to the thermalazation charm quark transport in QGP mean field effect, neglecting inelastic interaction, relaxation time approximation for elastic interaction analytic solution initial pQCD distribution Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, Charm Quark Thermalazation thermal parameters in relaxation time approximation energy and momentum conservation in collisions D meson production via coalescence on hadronization hypersurfaces transport distribution at hadronization hydrodynamic distribution at hadronization Ko, Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, charm quark pt distribution at b=7.2 fm in Au+Au 3. Charm Quark Thermalazation means complete thermalization, more low pt charm quarks in thermalization distribution Pengfei ZHUANGQuark Matter 2006, Shanghai, China, Nov. 14 20, Charm Quark Thermalazation charm quark V2 at b=7.2 fm in Au+Au V2 at pt > 1 GeV is very sensitive to if charm quarks are thermalized. numerical calculation on D meson is not yet finished.