Enhancement of alpha-particle formation near Sn-100

摘要

The superfluid tunneling model is applied to the calculation of ground-state-to-ground-state a decay in the even-even neutron-deficient Te-Ba nuclei. We show that there is a larger alpha-particle formation probability in nuclei of this region above Sn-100 when compared to analogous nuclei above Pb-208. This is consistent with the expected systematic variation of the pair gap Delta as a function of mass number. The recent experimental data on the a decay of the N = Z nuclei Te-104 and Xe-108 are shown to leave open the possibility of enhanced a-particle formation involving nucleon correlations beyond the standard treatment of like-nucleon pairing, which is the mechanism suggested as underlying "superallowed" alpha decay.