IN-MEDIUM NUCLEON-NUCLEON CROSS-SECTIONS FROM NONRELATIVISTIC REACTION MATRICES IN NUCLEAR-MATTER

In-medium nucleon-nucleon cross sections are calculated from reaction matrices of the nonrelativistic Brueckner approach. Calculated cross s ections are parametrized as a function of the incident energy and the nuclear density. The nonrelativistic cross sections are found to be re duced from free ones as observed in relativistic Brueckner calculation s. This reduction of the in-medium cross sections is ascribed to the f lux renormalization represented by an effective mass. It is pointed ou t that we should be careful to avoid double counting the effective mas s effects when in-medium cross sections calculated are applied in vari ous models of dynamical nuclear processes.