Analysis of nuclear structure in the nuclear chart and improvement to the gross theory of decay

Endo, Fumitaka*; Koura, Hiroyuki   

The gross theory, a global method of calculation for nuclear decay, is improved on the single-particle treatment. We analyzed the decay channel for the entire region of nuclides, and found that the allowed transition from ground to ground or low-energy states is suppressed systematically in the neighboring of doubly-magic heavier nuclei. It is mainly due to the shift of neutron and proton single particle levels in one major shell, and resulting the change in spin and parity between parent and daughter nuclei occurs. Under this consideration, the nuclear matrix elements for the allowed transition on the gross theory are suppressed in the above condition. In the vicinity of the doubly-magic numbers of neutron-rich nuclides such as nuclei with and , calculated half-lives are longer when we compere to the previous work, in which only mismatching in parity is considered. In the super-heavy neutron-rich nuclei with , half-lives is predicted to be longer due to the same mechanism.