Quasi-particle random phase approximation with quasi-particle-vibration coupling: application to the Gamow-Teller response of the superfluid nucleus $^{120}$Sn

TL;DR

This paper introduces a self-consistent QRPA+QPVC model with Skyrme interactions to accurately describe giant resonances in superfluid nuclei, successfully applied to the Gamow-Teller response of $^{120}$Sn.

Contribution

The paper develops a novel QRPA+QPVC model incorporating superfluidity effects for open-shell nuclei, enhancing the description of giant resonance line shapes.

Findings

Accurately reproduces the Gamow-Teller strength distribution in $^{120}$Sn.

Analyzes microscopic mechanisms involving QPVC and isoscalar pairing.

Demonstrates the importance of superfluidity in nuclear response modeling.

Abstract

We propose a self-consistent quasi-particle random phase approximation (QRPA) plus quasi-particle-vibration coupling (QPVC) model with Skyrme interactions to describe the width and the line shape of giant resonances in open-shell nuclei, in which the effect of superfluidity should be taken into account in both the ground state and the excited states. We apply the new model to the Gamow-Teller resonance in the superfluid nucleus $^{120}$Sn, including both the isoscalar spin-triplet and the isovector spin-singlet pairing interactions. The strength distribution in $^{120}$Sn is well reproduced and the underlying microscopic mechanisms, related to QPVC and also to isoscalar pairing, are analyzed in detail.