Modeling j / psi production and absorption in a microscopic nonequilibrium approach

TLDR: In this paper, the authors compared the effect of nuclear stopping and the role of leading hadrons on the performance of color-octet cross sections with one of distinct color-singlet states, evolving from small, color transparent configurations to their asymptotic sizes.

Abstract: Charmonium production and absorption in heavy ion collisions is studied with the ultrarelativisitic quantum molecular dynamics model. We compare the scenario of universal and time-independent color-octet dissociation cross sections with one of distinct color-singlet $J/\ensuremath{\psi},$ ${\ensuremath{\psi}}^{\ensuremath{'}}$, and ${\ensuremath{\chi}}_{c}$ states, evolving from small, color transparent configurations to their asymptotic sizes. Both purely hadronic scenarios are compared with the $\mathrm{pA}$ and $\mathrm{AB}$ data at SPS energies. The predicted rapidity dependence of $J/\ensuremath{\psi}$ suppression can be used to discriminate between the two scenarios experimentally. The importance of interactions with secondary hadrons and the applicability of thermal reaction kinetics to $J/\ensuremath{\psi}$ absorption are investigated. We discuss the effect of nuclear stopping and the role of leading hadrons. The dependence of the ${\ensuremath{\psi}}^{\ensuremath{'}}/J/\ensuremath{\psi}$ ratio on the model assumptions and the possible influence of refeeding processes are also studied.