Spin-isospin response of deformed neutron-rich nuclei in a self-consistent Skyrme energy-density-functional approach

TL;DR

This paper introduces a new self-consistent deformed pnQRPA framework using Skyrme energy-density functionals to study spin-isospin responses and beta-decay in neutron-rich deformed nuclei, with applications to Zr isotopes.

Contribution

The paper develops a novel self-consistent deformed pnQRPA method based on Skyrme functionals, incorporating T=0 pairing, to accurately predict Gamow-Teller strength distributions and beta-decay rates in deformed neutron-rich nuclei.

Findings

GT strength distributions are fragmented due to deformation.

Momentum-dependent interactions enhance GT giant resonance collectivity.

T=0 pairing significantly shortens beta-decay half-lives.

Abstract

We develop a new framework of the self-consistent deformed proton-neutron quasiparticle-random-phase approximation (pnQRPA), formulated in the Hartree-Fock-Bogoliubov (HFB) single-quasiparticle basis. The same Skyrme force is used in both the HFB and pnQRPA calculations except in the proton-neutron particle-particle channel, where an S=1 contact force is employed. Numerical application is performed for Gamow-Teller (GT) strength distributions and $\beta$-decay rates in the deformed neutron-rich Zr isotopes located around the path of the rapid-neutron-capture process nucleosynthesis. It is found that the GT strength distributions are fragmented due to deformation. Furthermore we find that the momentum-dependent terms in the particle-hole residual interaction leads to a stronger collectivity of the GT giant resonance. The T=0 pairing enhances the low-lying strengths cooperatively with the T=1 pairing correlation, which shortens the $\beta$-decay half lives by at most an order of magnitude. The new calculation scheme reproduces well the observed isotopic dependence of the $\beta$-decay half lives of deformed $^{100-110}$Zr isotopes.