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arXiv · 1207.6154

Coulomb energy difference as a probe of isospin-symmetry breaking in the upper fp-shell nuclei

K. Kaneko·T. Mizusaki·Y. Sun·S. Tazaki·G. de Angelis
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Abstract

The anomaly in Coulomb energy differences (CED) between the isospin T=1 states in the odd-odd N=Z nucleus 70Br and the analogue states in its even-even partner 70Se has remained a puzzle. This is a direct manifestation of isospin-symmetry breaking in effective nuclear interactions. Here, we perform large-scale shell-model calculations for nuclei with A=66-78 using the new filter diagonalization method based on the Sakurai-Sugiura algorithm. The calculations reproduce well the experimental CED. The observed negative CED for A=70 are accounted for by the cross-shell neutron excitations from the fp-shell to the g9/2 intruder orbit with the enhanced electromagnetic spin-orbit contribution at this special nucleon number.

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K. Kaneko, T. Mizusaki, Y. Sun, S. Tazaki, G. de Angelis. 2012-07-26. Coulomb energy difference as a probe of isospin-symmetry breaking in the upper fp-shell nuclei. https://doi.org/10.1103/physrevlett.109.092504

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