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

We perform a Markov chain Monte Carlo (MCMC) statistical analysis of a number of measured ground-state-to-ground-state single β⁺/electron-capture and β^- decays in the nuclear mass range of A =62 -142 . The corresponding experimental comparative half-lives (logf t values) are compared with the theoretical ones obtained by the use of the proton-neutron quasiparticle random-phase approximation (p n QRPA ) 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 p n QRPA framework. As far as available, measured half-lives for two-neutrino β β^- decays occurring in the studied isobaric chains are analyzed as well.