Mean free paths and in-medium scattering cross sections of energetic nucleons in neutron-rich nucleonic matter within the relativistic impulse approximation

TL;DR

This study investigates the behavior of energetic nucleons in neutron-rich matter, revealing how their mean free paths and scattering cross sections depend on energy, density, and isospin asymmetry using relativistic impulse approximation.

Contribution

It provides a detailed analysis of in-medium nucleon scattering properties, highlighting the isospin-splitting of mean free paths and the density dependence of cross sections at high energies.

Findings

Isospin-splitting of mean free paths changes sign at high energies.

In-medium nucleon-nucleon cross sections are largely independent of isospin asymmetry.

Cross sections increase linearly with density at high energies.

Abstract

The mean free paths and in-medium scattering cross sections of energetic nucleons in neutron-rich nucleonic matter are investigated using the nucleon optical potential obtained within the relativistic impulse approximation with the empirical nucleon-nucleon scattering amplitudes and the nuclear densities obtained in the relativistic mean field model. It is found that the isospin-splitting of nucleon mean free paths, sensitive to the imaginary part of the symmetry potential, changes its sign at certain high kinetic energy. The in-medium nucleon-nucleon cross sections are analytically and numerically demonstrated to be essentially independent of the isospin asymmetry of the medium and increase linearly with density in the high energy region where the relativistic impulse approximation is applicable.