$\beta$(EC) delayed fission in the heaviest nuclei

Abstract

Nuclear fission is one of the radioactive decay modes of heavy nuclei, and is a limiting factor in the existence of the superheavy elements. For decades, both experimental and theoretical works devoted to the study of fission have been performed, and are still ongoing. Among them, the so-called $\beta$ (electron capture)-delayed fission is of special interest. In this work, all known cases of electron-capture delayed fission in heavy nuclei were used to establish a semi-empirical approach that could quantitatively estimate the probability of the process. This framework was constructed based on a qualitative discussion of the fission-barrier shape, in contrast to a parabolic shape. The results show a strong effect of the fission-barrier shape on the delayed fission process. The predictions for yet unmeasured cases of electron-capture delayed fission in nuclei with atomic numbers in the wide range ( $79\leq Z\leq 119$) including the superheavy nuclei are given. It is suggested that $ \beta$-delayed fission manifests itself as one of the main decay modes of the superheavy nuclei, if $ \beta$ decay takes place.