Deformed shell model study of heavy N=Z nuclei and dark matter detection

TL;DR

This paper applies the deformed shell model to study heavy N=Z nuclei, specifically $^{66}$As, and explores its novel application in calculating dark matter detection rates using $^{73}$Ge.

Contribution

It demonstrates the effectiveness of the deformed shell model in describing nuclear structure and introduces its first application to dark matter detection rate calculations.

Findings

DSM accurately describes low-lying bands in $^{66}$As.

Structural change predicted at $8^+$ in $^{66}$As.

First application of DSM to dark matter detection rates.

Abstract

Deformed shell model (DSM) based on Hartree-Fock intrinsic states is applied to address two current problems of interest. Firstly, in the $f_{5/2}pg_{9/2}$ model space with jj44b effective interaction along with isospin projection, DSM is used to describe the structure of the recently observed low-lying $T=0$ and $T=1$ bands in the heavy odd-odd N=Z nucleus $^{66}$As. DSM results are close to the data and also to the shell model results. For the $T=1$ band, DSM predicts structural change at $8^+$ just as in the shell model. In addition, the lowest two $T=0$ bands are found to have quasi-deuteron structure above a $^{64}$Ge core and the $5^+$ and $9^+$ levels of the third $T=0$ band are found to be isomeric states. Secondly, in a first application of DSM to dark matter, detection rates for the lightest supersymmetric particle (a dark matter candidate) are calculated with $^{73}$Ge as the detector.