In the present work, we report a comprehensive shell-model study of the $\log ft$ values for the forbidden $\beta^-$ decay transitions in the north-east region of $^{ 208}$Pb. For this we have considered $^{ 210-215}$Pb $\rightarrow$ $^{ 210-215}$Bi and $^{ 210-215}$Bi $\rightarrow$ $^{ 210-215}$Po transitions. We have performed shell-model calculation using KHPE interaction in valence shell 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 $\log ft$ values are observed corresponding to $\beta^-$ decay from (8$^-$) isomeric state of $^{ 214}$Bi$^m$ at CERN-ISOLDE facility [Phys. Rev. C { \bf 104}, 054301 (2021)], and for the first time we have reported shell-model results for these transitions.
Categories: nucl-th