Different nucleon-nucleon cross sections and multifragmentation

Abstract

We present a systematic study of the dependence of the fragment production on the nucleon-nucleon cross section using the quantum molecular dynamics model as an event generator. We employ constant energy-dependent and in-medium cross sections. In our analysis, fragments are formed using a minimum spanning tree description. The fragment distribution with different cross sections at low energy is nearly the same. At higher energies, different nucleon-nucleon (NN) cross sections have small effects on fragment production for central collisions, whereas the fragment production is strongly influenced at semicentral and peripheral collisions. A larger NN cross section results in more intermediate mass fragments at peripheral collisions with a shift of the peak towards larger impact parameters. As a result, the rapidity distribution of fragments and the fragment flow is also affected by the choice of the cross section. This influence is reduced if fragments are constructed with a sophisticated algorithm such as the simulated annealing clusterization algorithm which searches for the most bound configuration of nucleons and fragments.