Enhanced J/Psi Production in Deconfined Quark Matter

Abstract

In high energy heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven and the Large Hadron Collider (LHC) at CERN, each central event will contain multiple pairs of heavy quarks. if a region of deconfined quarks and gluons is formed, a new mechanism for the formation of heavy quarkonium bound states will be activated. This is a result of the mobility of heavy quarks in the deconfined region, such that bound states can be formed from a quark and an antiquark which were originally produced in separate incoherent interactions. Model estimates of this effect for J/psi production at RHIC indicate that significant enhancements are to be expected. Experimental observation of such enhanced production would provide evidence for deconfinement unlikely to be compatible with competing scenarios.

Figures (3)

• Figure 1: Calculated $J/\psi$ formation in deconfined matter at several initial temperatures, $\Delta$y = 1, for central collisions at RHIC as a function of initial charm pair ($N_0$)and $J/\psi$ ($N_1$) values.
• Figure 2: Ratio of final $J/\psi$ to initial charm as a function of centrality. The solid symbols are with the inclusion of the new formation mechanism in the deconfined medium. Initial plasma temperature $T_0$ is coded by squares (300 MeV), circles (400 MeV), and diamonds (500 MeV). Different charm quark momentum distributions are indicated by the solid lines (thermal) and combinations of dashed and dotted lines ($\Delta$y = 1,2,3,4). The alternate screening model results are given by triangles, using $T_s$ = 200, 240, and 280 MeV. Curves with open symbols are the same calculations with the new formation mechanism omitted.
• Figure 3: Predicted energy dependence of $J/\psi$ at RHIC.