Nuclear $\beta^+$/EC decays in covariant density functional theory and the impact of isoscalar proton-neutron pairing

TL;DR

This paper develops a relativistic theoretical framework to study proton-neutron decays in various isotopes, highlighting the significant role of isoscalar pairing in accurately predicting decay half-lives.

Contribution

It introduces a self-consistent relativistic model incorporating isoscalar proton-neutron pairing to improve decay half-life predictions.

Findings

Isoscalar proton-neutron pairing reduces decay half-lives.

Model reproduces experimental half-lives with a universal pairing strength.

The approach is consistent with mechanisms in neutron-rich nuclei decays.

Abstract

Self-consistent proton-neutron quasiparticle random phase approximation based on the spherical nonlinear point-coupling relativistic Hartree-Bogoliubov theory is established and used to investigate the $\beta^+$/EC-decay half-lives of neutron-deficient Ar, Ca, Ti, Fe, Ni, Zn, Cd, and Sn isotopes. The isoscalar proton-neutron pairing is found to play an important role in reducing the decay half-lives, which is consistent with the same mechanism in the $\beta$ decays of neutron-rich nuclei. The experimental $\beta^+$/EC-decay half-lives can be well reproduced by a universal isoscalar proton-neutron pairing strength.