J/PSI SUPPRESSION IN HADRON-NUCLEUS COLLISIONS

We examine the production of J/psi 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 ccBAR pairs. We show that, at the energies of current fixed target experiments, J/psi 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/psi suppression at large x(F) is directly connected to nuclear shadowing in deeply inelastic scattering. We find that a 6-8 mb ccBAR-nucleon cross section is needed to explain the data on J/psi suppression if a simple incoherent multiple scattering formalism is used for the final state interactions. We then provide a more complete model to incorporate the effects of final state multiple soft scatterings. With only one parameter, this model can fit both the normalization and A dependence of the data for a variety of nuclei.