Investigation of bound state β− decay half-lives of bare atoms

Abstract

We investigate the bound state ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay of highly ionized atoms, in which the decay electron remains in a bound atomic state rather than being emitted into the continuum. A survey of 3344 nuclei is performed in order to search possible bound state ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay nuclei. We find that, for candidates $^{163}\mathrm{Dy}$, $^{193}\mathrm{Ir}$, $^{194}\mathrm{Au}$, $^{202}\mathrm{Tl}$, $^{205}\mathrm{Tl}$, $^{215}\mathrm{At}$, $^{222}\mathrm{Rn}$, $^{243}\mathrm{Am}$, and $^{246}\mathrm{Bk}$, the channel of ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay is completely forbidden in the neutral case but can be opened in the bare case. The corresponding bound-state ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay half-lives of these nuclei are predicted by using the Takahashi-Yokoi model, which are found to be significantly different from those in the neutral case.