Mass dependence and isospin dependence of short-range correlated pairs

TL;DR

This paper presents a geometrical model to analyze how short-range correlated nucleon pairs depend on target mass and isospin, explaining experimental cross-section trends with simple combinatorics.

Contribution

It introduces a transparent geometrical model that describes the mass and isospin dependence of short-range correlated pairs without additional assumptions.

Findings

The A dependence of ejection cross sections reflects nuclear density distributions.

Proton-proton vs. proton-neutron pair ratios can be understood through combinatorics.

The model provides a parametrization of the A dependence in short-range correlations.

Abstract

The target-mass number dependence of nucleon-nucleon pairs with short-range correlations is explored in a physically transparent geometrical model within a zero-range approximation. The observed $A$ dependence of 2-nucleon ejection cross sections in $(e,e')$ reactions is found to reflect the mass dependence of nuclear density distributions. A parametrization of this $A$ dependence is given. The $A$ dependence of proton-proton vs.\ proton-neutron pairs relative to $^{12}$C is also analyzed in this model. It can be understood using simple combinatorics without any additional isospin dependence.