High-lying Gamow-Teller excited states in the deformed nuclei, $^{76}\textrm{Ge}$ and $^{82}\textrm{Se}$, by the smearing of the Fermi surface in Deformed Quasi-particle RPA (DQRPA)

TL;DR

This paper investigates high-lying Gamow-Teller excited states in deformed nuclei $^{76}$Ge and $^{82}$Se, attributing their origin to Fermi surface smearing caused by nuclear deformation within the DQRPA framework, and compares results with experimental data.

Contribution

It introduces a detailed mechanism linking Fermi surface smearing due to deformation to high-lying GT states using DQRPA, explaining experimental observations.

Findings

High-lying GT states are explained by Fermi surface smearing.

The model reproduces strong peaks observed in experiments.

Fermi surface smearing accounts for GT strength quenching.

Abstract

With the advent of high analysis technology in detecting the Gamow-Teller (GT) excited states beyond one nucleon emission threshold, the quenching of the GT strength to the Ikeda sum rule seems to be recovered by the high-lying GT states. Moreover, in some nuclei, the stronger GT peaks than any other peaks appear explicitly in the high-lying excited states. We address that these high-lying GT excited states stems from the smearing of the Fermi surface by the increase of the chemical potential owing to the deformation within a framework of the deformed quasi-particle random phase approximation (DQRPA). Detailed mechanism leading to the smearing is discussed, and comparisons to the available experimental data are shown to explain the strong peaks on the high-lying GT excited states in a satisfactory manner.