Shell-model description for the properties of the forbidden β− decay in the region “northeast” of Pb208

Abstract

We report a comprehensive shell-model study of the $logft$ values for the forbidden ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay transitions in the region northeast of $^{208}\mathrm{Pb}$. For this we have considered $^{210\text{--}215}\mathrm{Pb}$ $\ensuremath{\rightarrow}$ $^{210\text{--}215}\mathrm{Bi}$ and $^{210\text{--}215}\mathrm{Bi}$ $\ensuremath{\rightarrow}$ $^{210\text{--}215}\mathrm{Po}$ transitions. We have performed shell-model calculation using the KHPE interaction in valence shells 82-126 for protons and 126-184 for neutrons without any truncation. We have also calculated half-lives and $Q$ values for the concerned nuclei. Recently several $logft$ values were observed corresponding to ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay from the (${8}^{\ensuremath{-}}$) isomeric state of $^{214}\mathrm{Bi}^{m}$ at the CERN-ISOLDE facility [Andel et al., Phys. Rev. C 104, 054301 (2021)], and for the first time we have reported shell-model results for these transitions.