Microscopic two-nucleon overlaps and knockout reactions from $^{12}$C

TL;DR

This study compares two-nucleon overlaps from shell-model and no-core shell-model calculations to predict knockout reaction cross sections from $^{12}$C, highlighting the sensitivity of results to the nuclear interactions used.

Contribution

It introduces NCSM-based two-nucleon overlaps with chiral interactions for knockout reaction predictions, providing insights into nuclear structure effects.

Findings

NCSM overlaps enhance $np$-removal cross sections to $^{10}$B states.

Cross sections are highly sensitive to the nuclear interactions employed.

Final-state measurements can validate the structure and overlaps used in models.

Abstract

The nuclear structure dependence of direct reactions that remove a pair of like or unlike nucleons from a fast $^{12}$C projectile beam are considered. Specifically, we study the differences in the two-nucleon correlations present and the predicted removal cross sections when using $p$-shell shell-model and multi-$\hbar\omega$ no-core shell-model (NCSM) descriptions of the two-nucleon overlaps for the transitions to the mass $A$=10 projectile residues. The NCSM calculations use modern chiral two-nucleon and three-nucleon (NN+3N) interactions. The $np$-removal cross sections to low-lying $T$=0, $^{10}$B final states are enhanced when using the NCSM two-nucleon amplitudes. The calculated absolute and relative partial cross sections to the low energy $^{10}$B final states show a significant sensitivity to the interactions used, suggesting that assessments of the overlap functions for these transitions and confirmations of their structure could be made using final-state-exclusive measurements of the $np$-removal cross sections and the associated momentum distributions of the forward travelling projectile-like residues.