High-spin intruder states in the mirror nuclei 31S and 31P

Mirror energy differences (MED) between excited states in the A = 31, T = 1/2 mirror pair S-31 and P-31 have been measured up to high spin yrast states of positive and negative parity. The mirror nuclei were populated in the Mg-24(C-12, an) and Mg-24(C-12, ap) reactions, respectively. For the first time the MED are described in the framework of the shell model in a valence space that includes three main shells. The theoretical MED values as a function of angular momentum indicate that the main contribution arises from the Coulomb interaction, however, the isospin symmetry breaking term is not at all negligible and needs to be considered to reproduce the experimental findings.

Automated summary

In this study, Mirror Energy Differences (MED) between excited states in the A=31, T=1/2 mirror pair S-31 and P-31 were measured up to high spin yrast states of positive and negative parity. The MED values were described in the framework of the shell model with main contributions from the Coulomb interaction, but the isospin symmetry breaking term was also found to be important for reproducing experimental findings.