Reexamination of nuclear structure properties and shape coexistence of nuclei around A70

TL;DR

This study reexamines the nuclear structure and shape coexistence of nuclei around A70 using IBM 1 and RMF models, analyzing energy levels, shapes, and decay properties to understand shape effects on nuclear behavior.

Contribution

It combines IBM 1, RMF, and pn QRPA models to analyze shape coexistence and decay properties of A70 nuclei, providing new insights into their structural characteristics.

Findings

Shape coexistence observed in A70 nuclei.

Half lives vary significantly with nuclear shape.

RMF calculations with DD ME2 match experimental half lives.

Abstract

We reexamine the nuclear structure properties of waiting point nuclei around A70 using the interacting boson model 1 (IBM 1) and the relativistic mean field (RMF) model. Effective density dependent meson exchange functional (DD ME2) and density dependent point coupling functional (DD PC1) were used for the RMF calculations. We calculated the energy levels, the geometric shapes, binding and separation energies of nucleons and quadrupole deformation parameters (\b{eta}2). The shape coexistence phenomena in A 70 nuclei (68Se, 70Se, 70Br, 70Kr, 72Kr, 74Kr, 74Rb, and 74Sr) was later investigated. Spherical and deformed shapes of the selected waiting point nuclei were computed using the IBM 1 and RMF models, respectively. The proton neutron quasiparticle random phase approximation (pn QRPA) model was used to calculate \b{eta} decay properties (Gamow Teller strength distributions, \b{eta} decay half lives, and branching ratios) of selected nuclei as a function of \b{eta}2. The results revealed a significant variation in calculated half lives and Gamow Teller strength distributions as the shape parameter was changed. The \b{eta}2 computed via DD ME2 functional resulted in half lives in best agreement with the measured data.