Flow of Nucleons and Fragments in 40Ar + 27Al Collisions Studied with AMD

Abstract

Collective transverse momentum flow of nucleons and fragments in intermediate energy 40Ar + 27Al collisions is calculated with the antisymmetrized molecular dynamics (AMD). The observed flow and its balance energy are reproduced very well by the calculation with the Gogny force which corresponds to the soft EOS of the nuclear matter. Especially the calculated absolute value of the fragment flow is larger than that of the nucleon flow in the negative flow region, which can be explained by the existence of two components of flow. In addition to many similarities, difference in the deuteron flow is found between 12C + 12C and 40Ar + 27Al collisions, and its origin is investigated by paying attention to the production mechanism of light fragments. We also investigate the dependence of the flow of nucleons and fragments on the stochastic collision cross section and the effective interaction, and conclude that the stiff EOS without momentum dependence of the mean field is not consistent to the experimental data.