Two-component approach to J/ψ production in high-energy heavy-ion collisions

The production of charmonia in ultrarelativistic heavy-ion collisions in investigated including two sources. These are a primordial contribution coupled with various phases of dissociation, and a statistical coalescence of c and c-bar quarks at the hadronization phase transition. Within a schematic fireball evolution, SPS data on J/gy production can be reasonably well reproduced. Remaining discrepancies in the ψ'/ψ ratio are discussed. Predictions for the J/ψ centrality dependence at RHIC energies are confronted with first data from PHENIX. The pertinent excitation function of the NJ/gy/Ncc-bar ratio exhibits a characteristic minimum structure signaling the transition from the standard J/ψ suppression scenario (SPS) to predominantly statistical production (RHIC)