Medium effects on [FORMULA]/[FORMULA] in heavy-ion collisions at intermediate energies

Based on the isospin-dependent transport model IBUU and on the scaling model according to nucleon effective mass, effects of elastic and inelastic NN scattering cross-sections on [FORMULA]/[FORMULA] in the neutron-rich reaction 48 Ca + 48 Ca at a beam energy of 400MeV/nucleon are studied. It is found that cross-section effects of both NN elastic and inelastic scatterings affect [FORMULA] , [FORMULA] and [FORMULA] productions as well as the value of [FORMULA]/[FORMULA] .