Shell-model study for allowed and forbidden $β^-$ decay properties in the mass region "south" of ${}^{208}$Pb

Abstract

The large-scale shell-model calculations have been performed for the neutron-rich nuclei in the south region of ${}^{208}$Pb in the nuclear chart. The ${\hat{I}}^2$-decay properties, such as the $\log ft$, average shape factor values, half-lives, and partial decay rates are calculated for these neutron-rich nuclei using recent effective interaction for the ${}^{208}$Pb region. These calculations have been performed without truncation in a particular model space for nuclei $N\le 126$; additionally, particle-hole excitations are included in the case of core-breaking nuclei ($Z\le 82,N>126$). An extensive comparison with the experimental data has been made, and spin parities of several states have been proposed.

16 pages, 6 figures