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¯ quarks at the hadronization phase transition. Within a schematic fireball evolution, SPS data on J/Ί production can be reasonably well reproduced. Remaining discrepancies in the ψ‧/ψ ratio are discussed. Predictions for the J/Ί centrality dependence at RHIC energies are confronted with first data from PHENIX. The pertinent excitation function of the N/N ratio exhibits a characteristic minimum structure signaling the transition from the standard J/Ί suppression scenario (SPS) to predominantly statistical production (RHIC).