Probing short-range correlations in asymmetric nuclei with quasi-free pair knockout reactions

TL;DR

This paper develops a reaction model to study short-range correlations in asymmetric nuclei through quasi-free two-nucleon knockout reactions, successfully comparing predictions with experimental data and exploring neutron excess effects.

Contribution

It introduces an approximate factorized cross section model for SRC-driven knockout reactions and validates it against experimental data, extending understanding of SRC in asymmetric nuclei.

Findings

Model reproduces experimental knockout reaction features.

Fair agreement with Brookhaven measurements.

Predicts SRC effects across carbon isotopes with varying neutron excess.

Abstract

Short-range correlations (SRC) in asymmetric nuclei with an unusual neutron-to-proton ratio can be studied with quasi-free two-nucleon knockout processes following the collision between accelerated ions and a proton target. We derive an approximate factorized cross section for those SRC-driven $p(A,p^{\prime} N_1 N_2)$ reactions. Our reaction model hinges on the factorization properties of SRC-driven $A(e, e^\prime N_1 N_2)$ reactions for which strong indications are found in theory-experiment comparisons. In order to put our model to the test we compare its predictions with results of $^{12}\text{C}(p,p^{\prime} pn)$ measurements conducted at Brookhaven National Laboratory (BNL) and find a fair agreement. The model can also reproduce characteristic features of SRC-driven two-nucleon knockout reactions, like back-to-back emission of the correlated nucleons. We study the asymmetry dependence of nuclear SRC by providing predictions for the ratio of proton-proton to proton-neutron knockout cross sections for the carbon isotopes $^{9-15}$C thereby covering neutron excess values $(N-Z)/Z$ between -0.5 and +0.5.