Medium modifications of the nucleon–nucleon elastic cross section in neutron-rich intermediate energy HICs

Several observables of unbound nucleons which are to some extent sensitive to the medium modifications of nucleon–nucleon elastic cross sections in neutron-rich intermediate energy heavy ion collisions are investigated. The splitting effect of neutron and proton effective masses on cross sections is discussed. It is found that the transverse flow as a function of rapidity, the Q zz as a function of momentum, and the ratio of halfwidths of the transverse to that of longitudinal rapidity distribution R t / l are very sensitive to the medium modifications of the cross sections. The transverse momentum distribution of correlation functions of two nucleons does not yield information on the in-medium cross section.