HEAVY-PARTICLE PRODUCTION IN A PARTON MODEL OF HADRON-NUCLEUS INTERACTIONS

Production of heavy particles in hA collisions is discussed in the Gri bov-Glauber framework with a simple parton model for the upper blob of the Gribov graph, which represents the interaction amplitude of the p rojectile with target nucleons. It is shown that them is a new energy scale E(M) proportional to M2R(A)/x. For heavy particles of mass M whi ch cannot interact with the nucleus (lepton pairs), the screening corr ections for E < E(M) have an anomalous A1 behaviour, so that the inclu sive cross section off nuclei also behaves as A1. Only at very high en ergies, E > E(M), the screening corrections have the normal Glauber be haviour resulting in an inclusive cross section that behaves like A(al pha) with alpha < 1. For heavy particles which can interact the screen ing is of the normal type at all energies, with an effective rescatter ing cross section that increases with x. General formulae for the incl usive cross sections valid at all energies are given.