# Isospin dependence in single-nucleon removal cross sections explained through valence-core destruction effects

## TL;DR

This paper explains the long-standing discrepancy in one-nucleon removal cross sections by incorporating core destruction effects, which depend on nucleon binding energy, improving agreement with experimental isospin asymmetry data.

## Contribution

It introduces an extended eikonal formalism that accounts for core destruction, providing a new explanation for the isospin dependence in knockout reaction cross sections.

## Key findings

- Core destruction significantly reduces cross sections for deeply bound nucleons.
- Including core destruction diminishes the isospin dependence of quenching factors.
- Results align better with transfer and (p,pN) reaction data.

## Abstract

The discrepancy between experimental data and theoretical calculations in one-nucleon removal reactions at intermediate energies (quantified by the so-called "quenching factors") and its dependence on the isospin asymmetry of the nuclei has been an open problem in nuclear physics for the last fifteen years. In this work, we propose an explanation for this long-standing problem, which relies on the inclusion of the process of core destruction due to its interaction with the removed nucleon. To include this effect, we extend the commonly used eikonal formalism via an effective nucleon density, and apply it to a series of nucleon knockout reactions. The effect of core destruction is found to depend strongly on the binding energy of the removed nucleon, leading to a significant reduction of the cross section for deeply bound nucleons, which reduces the isospin dependence of the "quenching factors", making them more consistent with the trends found in transfer and (p,pN) reactions.