J-Psi Suppression in Hadron-Nucleus Collisions

Abstract

We examine the production of J/$Ψ$ mesons in high energy hadron-nucleus collisions using models that account for both the initial state modification of parton distributions in nuclei and the final state interaction of the produced $c\bar c$ pairs. We show that, at the energies of current fixed target experiments, J/$Ψ$ production through quark-antiquark annihilation gives the largest contribution at $x_F > 0.5$, while gluon-gluon fusion dominates the production at smaller $x_F$. The observed J/$Ψ$ suppression at large $x_F$ is directly connected to nuclear shadowing in deeply inelastic scattering. We find that a $6\sim 8$mb $c\bar c$-nucleon cross section is needed to explain the data on J/$Ψ$ suppression if a simple incoherent multiple scattering formalism is used for the final state interactions.