J/ψ suppression and enhancement in Au plus Au collisions at the BNL RHIC

We consider J/psi production in heavy ion collisions at RHIC energies in the statistical coalescence model with exact (canonical ensemble) charm conservation. Charm quark-antiquark pairs are assumed to be created in primary hard parton collisions, but open and hidden charm particles are formed at the hadronization stage according to the laws of statistical mechanics. The dependence of the J/psi production on both the number of nucleon participants and the collision energy is studied. The model predicts J/psi suppression for low energies, whereas at the highest RHIC energy the model reveals J/psi enhancement. (C) 2002 Elsevier Science B.V. All rights reserved.