Statistical analysis of beta decays and the effective value of g_A in the proton-neutron quasiparticle random-phase approximation framework

TL;DR

This paper uses statistical methods to analyze beta decay data and determine the effective axial-vector coupling constant g_A within the pnQRPA nuclear model, providing insights into nuclear decay processes.

Contribution

It introduces a comprehensive MCMC statistical analysis of beta decay data to extract g_A values and uncertainties within the pnQRPA framework, including double beta decay data.

Findings

Estimated g_A values with uncertainties for various nuclei.

Consistency of theoretical half-lives with experimental data.

Insights into nuclear structure effects on beta decay.

Abstract

We perform a Markov Chain Monte Carlo (MCMC) statistical analysis of a number of measured ground-state-to-ground-state single $\beta^+$/electron-capture and $\beta^-$ decays in the nuclear mass range A = 62 - 142. The corresponding experimental comparative half-lives (log ft values) are compared with the theoretical ones obtained by the use of the proton-neutron quasiparticle random-phase approximation (pnQRPA) with G-matrix based effective interactions. The MCMC analysis is performed separately for 47 isobaric triplets and 28 more extended isobaric chains of nuclei to extract values and uncertainties for the effective axial-vector coupling constant g_A in nuclear-structure calculations performed in the pnQRPA framework. As far as available, measured half-lives for two-neutrino double beta-minus decays occurring in the studied isobaric chains are analyzed as well.