Neutron skin thickness and the transition from cluster decay to spontaneous fission in superheavy nuclei

Abstract

Understanding the competition between cluster decay and spontaneous fission is essential for elucidating

the stability and decay characteristics of neutron-rich superheavy nuclei. In this work, the density- dependent cluster model combined with the Wentzel-Kramers-Brillouin (WKB) approximation is

employed to investigate the competing decay modes of selected superheavy nuclei with atomic number Z>103. Cluster-decay penetrabilities, decay constants, together with spontaneous-fission barrier heights and half-lives, are calculated using the AME2020 nuclear mass evaluation and validated against the available experimental data from NUBASE2020. The calculations demonstrate that cluster decay is governed primarily by decay Q-values, barrier penetrability, shell effects, and daughter-nucleus configurations, whereas spontaneous-fission half-lives decrease systematically with increasing fissility as the calculated fission barriers are reduced. To probe the structural evolution of the investigated isotopic chains, the calculated decay characteristics are further

analysed in relation to neutron skin thickness. A transition from cluster-decay dominance to spontaneous- fission dominance is observed for nuclei exhibiting larger neutron skin thickness. The observed trends are

consistent with the systematic evolution of nuclear structure and decay energetics across the investigated isotopic chains, with neutron skin thickness serving as a structural indicator rather than an independent driver of the calculated decay properties. Comparison with the available experimental spontaneous-fission half-lives yields a root-mean-square deviation of 1.822, demonstrating satisfactory agreement with experiment. The present study establishes a systematic benchmark for assessing the competition between cluster decay and spontaneous fission in superheavy nuclei and provides a reference for the development and validation of microscopic models incorporating neutron-skin-dependent nuclear interactions.