Mirror Energy Differences at Large Isospin Studied through Direct Two-Nucleon Knockout

TL;DR

This study investigates mirror energy differences in specific nuclei using two-neutron knockout reactions, revealing the necessity of including isospin nonconserving interactions in shell-model calculations for accurate results.

Contribution

It provides the first spectroscopy data for excited states in 52Ni and 51Co and demonstrates the importance of isospin nonconserving effects in nuclear structure models.

Findings

Mirror energy differences are influenced by isospin nonconserving interactions.

Shell-model calculations require additional isospin nonconserving terms for accuracy.

Experimental data supports the presence of unknown isospin nonconserving effects.

Abstract

The first spectroscopy of excited states in 52Ni (Tz=2) and 51Co (Tz=-3/2) has been obtained using the highly selective two-neutron knockout reaction. Mirror energy differences between isobaric analogue states in these nuclei and their mirror partners are interpreted in terms of isospin nonconserving effects. A comparison between large scale shell-model calculations and data provides the most compelling evidence to date that both electromagnetic and an additional isospin nonconserving interactions for J=2 couplings, of unknown origin, are required to obtain good agreement.