Investigation of Nuclear Structure and $\beta$-decay Properties of As Isotopes

TL;DR

This study investigates the nuclear structure and beta-decay properties of arsenic isotopes using relativistic mean field and pnQRPA models, providing insights relevant for stellar evolution simulations.

Contribution

It combines RMF and pnQRPA models to accurately predict nuclear and decay properties of arsenic isotopes, enhancing understanding of stellar processes.

Findings

Calculated beta-decay half lives agree with experimental data within a factor of 10.

Predicted stellar decay rates are higher than shell model results at high temperature and density.

The study's results are valuable for modeling late-stage stellar evolution.

Abstract

The nuclear ground state properties of 67 80As nuclei have been investigated within the framework of relativistic mean field (RMF) approach. The RMF model with density dependent (DDME2) interaction is utilized for the calculation of potential energy curves and the nuclear ground state deformation parameters $\beta_2$ of selected As isotopes. Later, the $\beta$ decay properties of As isotopes were studied using the proton neutron quasi particle random phase approximation pnQRPA model. These include Gamow Tellar (GT) strength distributions, log ft values, $\beta$ decay half lives, stellar $\beta$ plus minus decays and stellar electron positron capture rates. The $\beta_2$ values computed from RMF model were employed in the on QRPA model as an input parameter for the calculations of $\beta$-decay properties for 67 80As. The calculated log ft values were in decent agreement with the measured data. The predicted $\beta$-decay half lives matched the experimental values within a factor of 10. The stellar rates were compared with the shell model results. Only at high temperature and density values, the sum of $\beta$ plus and electron capture rates had a finite contribution. On the other hand, the sum of $\beta$ negative and positron capture rates were sizeable only at low density and high temperature values. For all such cases, the pn QRPA rates were found to be bigger than the shell model rates up to a factor of 33 or more. The findings reported in the current investigation could prove valuable for simulating the late stage stellar evolution of massive stars.