Correlations in intermediate-energy two-proton removal reactions

TL;DR

This study investigates two-proton removal reactions from neutron-rich 28Mg, revealing that over half of the events involve correlated proton pairs, providing insights into nucleon pair correlations in exotic nuclei.

Contribution

It demonstrates that a significant portion of two-proton removal events are consistent with spin-zero correlated pairs, linking reaction outcomes to shell-model configurations.

Findings

56(12)% of events show proton correlations consistent with pair-removal

The observed fraction aligns with shell-model predictions of 64% for spin S=0 pairs

Results suggest a new probe for nucleon pair correlations in exotic nuclei

Abstract

We report final-state-exclusive measurements of the light charged fragments in coincidence with 26Ne residual nuclei following the direct two-proton removal from a neutron-rich 28Mg secondary beam. A Dalitz-plot analysis and comparisons with simulations show that a majority of the triple- coincidence events with two protons display phase-space correlations consistent with the (two-body) kinematics of a spatially-correlated pair-removal mechanism. The fraction of such correlated events, 56(12) %, is consistent with the fraction of the calculated cross section, 64 %, arising from spin S = 0 two-proton configurations in the entrance-channel (shell-model) 28Mg ground state wave function. This result promises access to an additional and more specific probe of the spin and spatial correlations of valence nucleon pairs in exotic nuclei produced as fast secondary beams.