Single universal curve forαdecay derived from semi-microscopic calculations

Abstract

The universal curve is one of the simple ways to get preliminary information about the Alpha-decay half-life times of heavy nuclei. We try to find parameterization for the universal curve of Alpha decay based on semi-microscopic calculations, starting from the realistic M3Y-Reid nucleon-nucleon interaction. Within the deformed density-dependent cluster model, the penetration probability and the assault frequency are calculated using the WKB penetration probability. The deformations of daughter nuclei and the ground-state spin and parity of the involved nuclei are considered. We found that it is accurate enough to express the assault frequency, for all studied decays, either as a function of the mass number of the parent nuclei or as a constant average value. The average preformation probability of the Alpha cluster inside four groups of 166 even(Z)-even(N), 117 odd-even, 141 even-odd, and 72 odd-odd Alpha-emitters are obtained, individually. The effect of participating unpaired nucleons in the involved nuclei, as well as the influence of any differences in their ground-state spin and/or parity, appears in the obtained average values of the preformation probability. Based on the calculated WKB penetration probability, we suggested a single universal curve for Alpha decay, with only one parameter. This parameter varies according to the classified four groups. It includes the preformation probability and the average assault frequency, in addition to the pairing contribution.