Recombinant charmonium in strongly coupled quark-gluon plasma

Abstract

We update our previous work of a Langevin-with-interaction model for charmonium in heavy-ion collisions, by considering the effect due to recombination. We determine the contribution to J/psi yields from charm-anticharm pairs whose constituent quarks originate from two different hard processes. Like the surviving J/psi states, the recombinant J/psi also undergo both a stochastic interaction, determined by a hydrodynamical simulation of the heavy-ion collision, and an interaction determined by the heavy quark-antiquark potentials measured on the lattice for appropriate temperatures. From the results of these simulations, we determine both the direct and the recombinant contribution to the J/psi yields for RHIC conditions, and find that for central collisions, between 30% and 50% of the J/psi yield is due to recombinant production. We compare our results with other models and look for how the recombinant contribution differs from the surviving contribution in the differential p_t yields. Including the recombinant contribution improves the agreement with the latest analysis of charmonium at RHIC, which shows an absence of anomalous suppression except in the most central collisions.