Effects of Quasiparticle-Vibration Coupling on Gamow-Teller Strength and $\beta$ Decay with the Skyrme Proton-Neutron Finite-Amplitude Method

TL;DR

This paper introduces a novel extension of the proton-neutron finite-amplitude method incorporating quasiparticle-phonon coupling, significantly enhancing the accuracy of Gamow-Teller strength and beta-decay rate calculations in deformed nuclei.

Contribution

It develops a new approach to include beyond-QRPA correlations in Skyrme-based calculations, improving agreement with experimental data for deformed nuclei.

Findings

Enhanced agreement with experimental Gamow-Teller strength distributions.

Significant improvement in beta-decay rate predictions.

First implementation of quasiparticle-phonon coupling in this context.

Abstract

We adapt the proton-neutron finite-amplitude method, which in its original form is an efficient implementation of the Skyrme quasiparticle random phase approximation, to include the coupling of quasiparticles to like-particle phonons. The approach allows us to add beyond-QRPA correlations to computations of Gamow-Teller strength and $\beta$-decay rates in deformed nuclei for the first time. We test the approach in several deformed isotopes for which measured strength distributions are available. The additional correlations dramatically improve agreement with the data, and will lead to improved global $\beta$-decay rates.