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J/ Ψ Transport in QGP and Pt Distribution at SPS and RHIC. Xianglei Zhu, Pengfei Zhuang (Tsinghua Univ.) Nu Xu (LBNL).
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J/Ψ Transport in QGP and Pt Distribution at SPS and RHIC Xianglei Zhu, Pengfei Zhuang (Tsinghua Univ.) Nu Xu (LBNL) Motivation J/Ψ transport in QGP QGP evolution J/ΨPt distribution and elliptic flow Conclusions ICHEP04 Beijing
Motivation J/Ψ suppression:an important signature of QGPNormal suppression:nuclear absorption Anomalous suppression:due to QGP or comovers Questions: 1)J/Ψ production mechanism at RHIC: initial gluon fusion or coalescence at hadronization?2)Almost all models can describe the suppression! Can Pt distribution help us to understand the production mechanism ? ICHEP04 Beijing
Idea of this work ●J/Ψ is produced via initial gluon fusion, no coalescence ● J/Ψ transport in QGP and is anomalously suppressed by gluons ● QGP evolution is controlled by ideal hydrodynamics ● focus on Pt distribution ICHEP04 Beijing
J/Ψ transport equation loss term: anomalous suppression gluon distribution flux factor gluonic dissociation process Initial condition:normal suppression Normal Pt broadening due to Cronin effect ICHEP04 Beijing
Gluonic dissociation process in QGP standard cross sections:(Bhanot, Peskin,1979) :gluon energy : binding energy of J/Ψ ICHEP04 Beijing
Medium evolution Hydrodynamics: EoS: Lattice result Initial condition: determined by (Kolb, Heinz, Rapp) Freeze-out: ICHEP04 Beijing
Bjorken space-time evolution for medium hydrodynamics and J/Ψ transport analytic solution Hufner, Zhuang, 2003 ICHEP04 Beijing
Suppression and Pt distribution at SPS ICHEP04 Beijing
Suppression and Pt distribution at RHIC J/Ψ formation time > collision time ICHEP04 Beijing
Driving force of V2 y x ●Primordial production via gluon fusion: 1)leakage effect of anomalous suppression 2)interaction with thermalized partons However, J/Ψ does not participate in the collective expansion! ●Statistical production at thermalization: c quarks participate in the collective expansion! ICHEP04 Beijing
Elliptic flow at SPS ICHEP04 Beijing
Elliptic flow at RHIC Greco, Ko, Rapp V2 with primordial production mechanism is only 7% of V2 with coalescence mechanism ! ICHEP04 Beijing
Conclusions ● J/Ψ transport + medium hydrodynamics can explain both the suppression and Pt distribution ● V2 can differentiate initial production from coalescence at hadronization ICHEP04 Beijing