Nature of Isomerism in Exotic Sulfur Isotopes

Abstract

We clarify the origin of the anomalously hindered $E2$ decay from the ${4}_{1}^{+}$ level in $^{44}\mathrm{S}$ by performing a novel many-body analysis in the shell model. Within a unified picture about the occurrence of isomerism in neutron-rich sulfur isotopes, the ${4}_{1}^{+}$ state is demonstrated to be a $K=4$ isomer dominated by the two-quasiparticle configuration $\ensuremath{\nu}{\mathrm{\ensuremath{\Omega}}}^{\ensuremath{\pi}}=1/{2}^{\ensuremath{-}}\ensuremath{\bigotimes}\ensuremath{\nu}{\mathrm{\ensuremath{\Omega}}}^{\ensuremath{\pi}}=7/{2}^{\ensuremath{-}}$. The ${4}_{1}^{+}$ state in $^{44}\mathrm{S}$ is a new type of high-$K$ isomer which has significant triaxiality.