Unfavoredαdecay from ground state to ground state in the range53≤Z≤91

Abstract

Within the density-dependent cluster model, we have systematically investigated partial $\ensuremath{\alpha}$-decay half-lives of ground-state (g.s.)-to-g.s. transitions. Emphasis is placed on the unfavored $\ensuremath{\alpha}$ transitions in the range $53\ensuremath{\le}Z\ensuremath{\le}91$ of both odd-$A$ and odd-odd nuclei. The $\ensuremath{\alpha}$-preformation factor is estimated by means of the multiplication of the valence proton and neutron numbers ${N}_{P}{N}_{N}$, in addition to the constant formation factor for one kind of nuclei. By introducing a centrifugal term, the previous empirical relation for $\ensuremath{\alpha}$-decay half-lives of our group is improved to reproduce a large number of experimental data including these unfavored transitions. Whatever concerns the theoretical calculation or the analytical expression, the agreement between theory and experiment is satisfied. This indicates that these studied unfavored g.s.-to-g.s. $\ensuremath{\alpha}$ decays can be reasonably described within the present approach extended from the treatment of favored ones.