Effects of quasiparticle-vibration coupling on Gamow-Teller strength and β decay with the Skyrme proton-neutron finite-amplitude method

The authors extend the proton-neutron finite-amplitude method, an iterative and efficient form of the Skyrme quasiparticle random-phase approximation that needs no diagonalization of the p00exn QRPA matrix, for the coupling of quasiparticles to like-particle phonons. With this approach one can add beyond-QRPA correlations to computations of important nuclear properties such as Gamow-Teller strength and β-decay rates in deformed nuclei. The results show improved agreement with existing data for several deformed nuclei, a promising step toward a more reliable framework for large-scale β-decay calculations needed, e.g., for r-process modeling.