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夸克胶子等离子体中 J/ Ψ 的 压 低和重 产 生 J/ Ψ Suppression and Regeneration in Quark-Gluon Plasma

夸克胶子等离子体中 J/ Ψ 的 压 低和重 产 生 J/ Ψ Suppression and Regeneration in Quark-Gluon Plasma. Pengfei ZHUANG ( 庄鹏飞 ) Tsinghua University, Beijing ( 清华大学，北京 ).

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夸克胶子等离子体中 J/ Ψ 的 压 低和重 产 生 J/ Ψ Suppression and Regeneration in Quark-Gluon Plasma

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  1. 夸克胶子等离子体中J/Ψ的压低和重产生J/Ψ Suppression and Regeneration in Quark-Gluon Plasma Pengfei ZHUANG (庄鹏飞) Tsinghua University, Beijing (清华大学，北京) 1. 引言 Motivation and Our Idea 2. 论证 J/Ψ Transport in QGP 3. 结果 Comparison with RHIC Data 4. 总结 Summary with Li YAN (严力), Xianglei ZHU(朱相雷) of Tsinghua and Nu XU (许怒) of LBNL nucl-th/0608010 (PRL, accepted) PLB607,107(2005) Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  2. 1. Motivation 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 isthe ratio of regenerated to initially produced J/ s ? how to differentiate J/ψ regeneration mechanisms ? Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  3. 1. Motivation our treatment ● both initial production and continuousregeneration in QGP ● suppression and regeneration via gluon dissociation and the inverse process ● transport equation for J/Ψ + hydrodynamic equation for QGP ●two limits for charm quark distribution: no interaction limit and thermalization limit Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  4. 2. J/Ψ Transport in QGP ●transverse transport equation with loss and gain terms in central rapidity region: : suppression in QGP : continuous regeneration in QGP distribution function: assumption: 40% of final state J/Ψs is from the feed-down of ●analytic solution first term: initial production, second term: continuous regeneration, both suffer suppression in QGP ●initial condition: p_t broadening due to Cronin effect Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  5. 2. J/Ψ Transport in QGP ●loss and gain terms via gluon dissociation perturbative calculation with nonrelativistic Coulomb potential (Peskin, Bhanot …) via detailed balance thermal gluon distribution controlled by hydrodynamics ●two limits of charm quark distribution:weak interaction limit, nuclear geometry pQCD distribution (Thews,…) strong interaction limit, thermal distribution controlled by hydrodynamics ●suppression and regeneration in hadron gas are neglected, since the hadron density is much lower than the gluon density Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  6. 2. J/Ψ Transport in QGP ●1+2 dimensional ideal hydrodynamics of QGP in thermal distributions ●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 Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  7. 3. Comparison with RHIC Data ●yield PHENIX data nucl-ex/0611020 hep-ex/0611020 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. Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  8. 3. Comparison with RHIC Data ● transverse momentum PHENIX data nucl-ex/0611020 hep-ex/0611020 regeneration is definitely important in central collisions, thermal scenario looks better to fit the data. Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  9. 3. Comparison with RHIC Data ● V2 at b=7.8 fm 1) initial V2 is small, V2 at SPS is really very small,see Gianluca Usai, this conference2)regenerated V2 is large3) 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 Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  10. 3. Comparison with RHIC Data ●ratio of regenerated to initially produced J/Ψ’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 Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  11. 4. Summary ● a J/Ψ 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/Ψare eaten up by QGP, and any J/Ψ behavior is dominated by the regeneration. ● V2 can differentiate sudden from continuous regeneration We thank R.Rapp. H.Stocker, R.Thews and R.Vogt for helpful discussions Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  12. Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  13. 5. 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 Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  14. 3. Charm Quark Thermalazation ● thermal parameters in relaxation time approximation energy and momentum conservation in collisions ● D meson production via coalescence on hadronization hypersurfaces Ko,… transport distribution at hadronization hydrodynamic distribution at hadronization Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  15. 3. Charm Quark Thermalazation ● charm quark pt distribution at b=7.2 fm in Au+Au means complete thermalization, more low pt charm quarks in thermalization distribution Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

  16. 3. 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. Quark Matter 2006, Shanghai, China, Nov. 14 – 20, 2006

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