On the $\beta$-decay of $^{186}$Hg

TL;DR

This study measures the Gamow-Teller strength distribution of $^{186}$Hg decay using total absorption gamma spectroscopy, compares it with QRPA calculations, and explores nuclear shape mixing effects.

Contribution

It provides the first experimental Gamow-Teller strength distribution for $^{186}$Hg decay and introduces a new analysis approach for X-ray gated total absorption spectra.

Findings

Prolate configurations dominate in both parent and daughter nuclei.

An upper limit for the oblate component in the parent nucleus was established.

Experimental data aligns best with theoretical models assuming prolate shapes.

Abstract

The Gamow-Teller strength distribution of the decay of $^{186}$Hg into $^{186}$Au has been determined for the first time using the total absorption gamma spectroscopy technique and has been compared with theoretical QRPA calculations using the SLy4 Skyrme force. The measured Gamow-Teller strength distribution and the half-life are described by mixing oblate and prolate configurations independently in the parent and daughter nuclei. The best description of the experimental beta strength is obtained with dominantly prolate components for both parent $^{186}$Hg and daughter $^{186}$Au. The approach also allowed us to determine an upper limit of the oblate component in the parent state. The complexity of the analysis required the development of a new approach in the analysis of the X-ray gated total absorption spectrum.