Isospin symmetry breaking and large-scale shell-model calculations with the Sakurai-Sugiura method

Takahiro Mizusaki,Yang Sun,Shigeru Tazaki,Kazunari Kaneko

doi:10.1051/epjconf/20159301051

Abstract

Recently isospin symmetry breaking for mass 60-70 region has been investigated based on large-scale shell-model calculations in terms of mirror energy differences (MED), Coulomb energy differences (CED) and triplet energy differences (TED). Behind these investigations, we have encountered a subtle problem in numerical calculations for odd-odd N = Z nuclei with large-scale shell-model calculations. Here we focus on how to solve this subtle problem by the Sakurai-Sugiura (SS) method, which has been recently proposed as a new diagonalization method and has been successfully applied to nuclear shell-model calculations. The isospin symmetry breaking is one of the current topics in nuclear structure physics. An asymmetry be- tween spectra of isospin analogue states with mirror pair nuclei has been extensively investigated in the upper sd− and the lower fp −shell regions (1), and in mass 60-70 region (2-6). This asymmetry, that is, isospin symmetry breaking arises partly due to the Coulomb force and partly due to the strong nucleon-nucleon interaction. To analyze this isospin symmetry breaking, mirror en- ergy differences (MED) (7), Coulomb energy differences (CED)(8) and triplet energy differences(TED) (7) have been discussed. The MED is a measure of charge sym- metry breaking in an effective interaction and is defined as

Highlights

The isospin symmetry breaking is one of the current topics in nuclear structure physics
The lower f p−shell regions [1], and in mass 60-70 region [2,3,4,5,6]. This asymmetry, that is, isospin symmetry breaking arises partly due to the Coulomb force and partly due to the strong nucleon-nucleon interaction
The mirror energy differences (MED) is a measure of charge symmetry breaking in an effective interaction and is defined as

Summary

Introduction

The isospin symmetry breaking is one of the current topics in nuclear structure physics. The MED is a measure of charge symmetry breaking in an effective interaction and is defined as J,T Tz is the excitation energies of analog states with spin J and isospin T, Tz. The TED of T = 1 states in triplet nuclei is a measure of the charge-independence breaking and is defined as For the TED, we have to evaluate the energy of the T = 1 and Tz = 0 state for odd-odd N = Z nuclei precisely, employing shell-model calculations with isospin non-conserving interactions [5, 6].

Results

Conclusion