New local mass relation for isobaric analogue states and isospin-nonconserving forces

Abstract

In this paper a new local mass relation is constructed for isobaric analogue states of four relating neighboring nuclei. The standard deviation from a linear fit of experimental data is 20--70 keV. The systematics of the local mass relation is discussed in terms of an empirical Coulomb energy formula and the isobaric multiplet mass equation. The local relation for nuclei in the $pf$ shell is studied in the framework of the microscopic shell model. The results demonstrate the key roles played by the Coulomb interaction and an effective isospin-nonconserving nucleon-nucleon interaction in our new mass relation.