Evidence for the general dominance of proton shells in low-energy fission

A regular pattern, revealing the leading role of light-fragment nuclear charge, is found to emerge from a consistent analysis experimental information collected recently on low-energy asymmetric fission neutron-deficient nuclei around lead. The observation corroborated by theoretical investigation within microscopic framework, suggesting importance proton configurations driven quadrupole-octupole correlations. This in contrast earlier interpretations terms dominant neutron shells. survey wider area chart semi-empirical approach points lack understanding competition between different underlying macroscopic and forces quantitative manner. Combined with previously identified stabilizing forces, present finding shows striking connection “old” (actinide) “new” (pre-actinide) islands which could steer strive for unified theory fission.