Spectroscopy of proton-rich 66^Se up to J^{\pi} = 6^+: isospin-breaking effect in the A = 66 isobaric triplet

TL;DR

This paper investigates the energy differences in the A=66 isobaric triplet, revealing isospin-breaking effects and highlighting the need for additional interactions beyond Coulomb forces, through experimental spectroscopy and shell-model calculations.

Contribution

It provides new experimental data on 66^Se excited states and compares these with shell-model predictions, emphasizing the role of isospin non-conserving interactions.

Findings

Triplet energy differences follow the negative trend in the f_7/2 shell.

Experimental data supports the need for additional isospin non-conserving interactions.

Shell-model calculations indicate the Coulomb isotensor part alone is insufficient.

Abstract

Candidates for three excited states in the 66^Se have been identified using the recoil-{\beta} tagging method together with a veto detector for charged-particle evaporation channels. These results allow a comparison of mirror and triplet energy differences between analogue states across the A = 66 triplet as a function of angular momentum. The extracted triplet energy differences follow the negative trend observed in the f_7/2 shell. Shell-model calculations indicate a continued need for an additional isospin non-conserving interaction in addition to the Coulomb isotensor part as a function of mass.