Theoretical studies on α -decay half-lives of N=125, 126, and 127 isotones

Abstract

The $\ensuremath{\alpha}$ decays of exotic $N=125$, 126, and 127 isotones, including two new isotopes $^{219}\mathrm{Np}$ [Phys. Lett. B 777, 212 (2018)] and $^{220}\mathrm{Np}$ [Phys. Rev. Lett. 122, 192503 (2019)], are studied by using the improved Buck-Merchant-Perez cluster model with the charge-dependent $\ensuremath{\alpha}$-preformation factors. The experimental half-lives of $\ensuremath{\alpha}$ decays varying from $2.50\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ to $6.00\ifmmode\times\else\texttimes\fi{}{10}^{26}\phantom{\rule{0.28em}{0ex}}\mathrm{s}$ are reproduced within a factor of $\ensuremath{\approx}2$. Noticeably, the theoretical $\ensuremath{\alpha}$-decay half-lives of the new isotopes $^{219,220}\mathrm{Np}$ are also in good agreement with the experimental data. Furthermore, the $\ensuremath{\alpha}$-decay half-lives of some undiscovered $N=125$, 126 and 127 isotones are predicted, which could be useful for future experimental studies on the robustness of the magic number $N=126$.