The recent experimental observation of isospin symmetry breaking (ISB) in the ground states of the T = 3/2 mirror pair Sr Br is theoretically studied using large-scale shell model calculations. The large valence space and the successful PFSDG-U effective interaction used for the nuclear part of the problem capture possible structural changes and provide a robust basis to treat the ISB effects of both electromagnetic and non-electromagnetic origin. The calculated shifts and mirrorenergy-differences are consistent with the inversion of the I= 1/2−, 5/2− states between Sr Br, and suggest that the role played by the Coulomb interaction is dominant. An isospin breaking contribution of nuclear origin is estimated to be ≈ 25 keV.

中文翻译：

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镜对 Sr73−Br73 中的同位旋对称性破缺

最近对 T = 3/2 镜对 Sr Br 基态中同位旋对称性破缺 (ISB) 的实验观察使用大规模壳模型计算进行了理论研究。用于问题核部分的大价空间和成功的 PFSDG-U 有效相互作用捕获了可能的结构变化，并为处理电磁和非电磁起源的 ISB 效应提供了可靠的基础。计算的位移和镜像能量差与 Sr Br 之间的 I= 1/2-, 5/2- 状态的反转一致，并表明库仑相互作用所起的作用占主导地位。核起源的同位旋破坏贡献估计为 ≈ 25 keV。