Color degrees of freedom in nuclear collisions and charmonium suppression

Abstract

In high energy nuclear collisions, the Glauber model is commonly used to evaluate $J/\psi$ suppression due to inelastic interaction with colorless bound nucleons. This requires an effective value for the $J/\psi$-nucleon absorption cross section which is larger than theoretically expected. On the other hand, multiple nucleon-nucleon collisions mediated by color exchange interactions, excite their color degrees of freedom. We investigate the importance of this effect and conclude that the related corrections are important to explain the effective value extrapolated from experiment.