Coulomb and nuclear excitation in intermediate-energy heavy-ion collisions.

Abstract

Following previous works where the field of application of Glauber methods were extended to heavy-ion scattering in the energy range of 30--400 MeV/nucleon, we develop here a formalism which includes both Coulomb and nuclear excitation processes and explicitly accounts for the effects arising from the energy difference in different channels. First order inelastic excitations are described in the framework of a distorted wave eikonal approximation; in this connection nuclear phase shifts and form factors are described in terms of microscopic nucleon-nucleon interactions while the Coulomb excitation is described through a proper manipulation of phenomenological form factors. Several specific examples are discussed. The interest is then focused on second-order processes, more specifically on the effects introduced in the elastic channel by the coupling to the inelastic channels, and the corresponding Coulomb and nuclear polarization potentials are derived and discussed. On the ground of these achievements a general formalism is built up, capable of describing coupled-channel problems at any order of scattering. Due to the eikonal propagation, the multichannel multistep series leads to simple algebraic forms for each partial-wave scattering matrix, which involve powers of a channel matrix whose elements only depend on the impact parameter.