NUCLEON-NUCLEON CROSS-SECTIONS IN NUCLEAR-MATTER

We provide a microscopic calculation of neutron-proton and neutron-neu tron cross sections in symmetric nuclear matter at various densities, using the Brueckner-Hartree-Fock approximation scheme with the Paris p otential. We investigate separately the medium effects on the effectiv e mass and on the scattering amplitude. We determine avenge cross sect ions suitable for application in the dynamical simulation of heavy ion collisions, including a parametrization of their energy and density d ependence.