Pauli blocking and medium effects in nucleon knockout reactions

TL;DR

This paper investigates how medium modifications, including Pauli blocking and density effects, influence nucleon knockout reactions, revealing up to 10% changes in cross sections especially in halo nuclei at energies 50-300 MeV/nucleon.

Contribution

It introduces a comparative analysis of free and medium-modified NN cross sections using various theoretical approaches within the eikonal approximation.

Findings

Medium effects can alter knockout cross sections by up to 10%.

The impact is more significant in reactions involving halo nuclei.

Density-dependent modifications are crucial for accurate reaction modeling.

Abstract

We study medium modifications of the nucleon-nucleon (NN) cross sections and their influence on the nucleon knockout reactions. Using the eikonal approximation, we compare the results obtained with free NN cross sections with those obtained with a purely geometrical treatment of Pauli-blocking and with NN obtained with more elaborated Dirac-Bruecker methods. The medium effects are parametrized in terms of the baryon density. We focus on symmetric nuclear matter, although the geometrical Pauli-blocking allows for the treatment of asymmetric nuclear matter. It is shown that medium effects can change the nucleon knockout cross sections and momentum distributions up to 10% in the energy range E=50-300 MeV/nucleon. The effect is more evident in reactions involving halo nuclei.