Low-Energy Gamow-Teller Transitions in deformed $N = Z$ odd-odd Nuclei

TL;DR

This paper investigates low-energy Gamow-Teller transitions in deformed odd-odd N=Z nuclei, revealing how core deformation and intrinsic spin coupling cause GT strength fragmentation, linked to SU(4) symmetry breaking.

Contribution

The study introduces a combined isospin projected antisymmetrized molecular dynamics and generator coordinate method to analyze GT transitions in deformed nuclei, highlighting the role of core deformation and spin coupling.

Findings

GT strength is fragmented into two states due to deformation.

Coupling of intrinsic spin with core deformation influences GT fragmentation.

SU(4) symmetry breaking is linked to GT strength fragmentation.

Abstract

We have investigated the Gamow-Teller transitions from ${}^{22}\textrm{Ne}$ to ${}^{22}\textrm{Na}$ by applying the isospin projected antisymmetrized molecular dynamics combined with generator coordinate method. We have found that the GT strength from $^AZ(J^\pi T)={}^{22}\textrm{Ne}(0_1^+1)$ is fragmented into two final states ${}^{22}\textrm{Na}(1_{1,2}^+0)$, which belong to $K=0$ and $K=1$ bands constructed by a prolately deformed $^{20}$Ne core with a $S=1$ proton-neutron ($pn$) pair. Coupling of the intrinsic-spin of the $pn$ pair with the core deformation play an important role in the GT fragmentation. The symmetry breaking in the intrinsic-spin rotation leads to the $SU(4)$-symmetry breaking of the $NN$ pair and causes the GT fragmentation. We have compared the features of the GT transitions with those for ${}^{10}\textrm{Be}\to{}^{10}\textrm{B}$ and discuss the link of the $SU(4)$-symmetry and the GT fragmentation in the deformed systems.