Transport model study of nuclear stopping in heavy ion collisions over an energy range from 0.09A GeV to 160A GeV

TL;DR

This study uses a modified UrQMD transport model to analyze nuclear stopping in heavy ion collisions across a wide energy range, highlighting the effects of the equation of state and medium modifications on collision dynamics.

Contribution

It introduces a comprehensive transport model incorporating mean field potentials and medium effects, providing new insights into nuclear stopping mechanisms at various energies.

Findings

Nuclear stopping is affected by the stiffness of the equation of state.

Medium modifications of nucleon-nucleon cross sections influence stopping at SIS energies.

The two-bump structure in proton rapidity distribution at SPS energies is explained by pre-formed hadron potentials.

Abstract

Nuclear stopping in the heavy ion collisions over a beam energy range from SIS, AGS up to SPS is studied in the framework of the modified UrQMD transport model, in which mean field potentials of both formed and "pre-formed" hadrons (from string fragmentation) and medium modified nucleon-nucleon elastic cross sections are considered. It is found that the nuclear stopping is influenced by both the stiffness of the equation of state and the medium modifications of nucleon-nucleon cross sections at SIS energies. At the high SPS energies, the two-bump structure is shown in the experimental rapidity distribution of free protons, which can be understood with the consideration of the "pre-formed" hadron potentials.