The effect of restoration of broken SU(4) symmetry on [formula omitted] decay rates

Abstract

The effect of restoration of SU(4) symmetry violations stemming from the mean field approximation on the 2νβ−β− decay amplitudes and half-lives for Ge76→Se76, Se82→Kr82, Zr96→Mo96 and Mo100→Ru100 decay systems is investigated within the framework of the proton–neutron quasi-particle random phase approximation (pnQRPA) method. In this respect, the broken SU(4) symmetry property of the central quasi-particle mean field term is restored by using Pyatov's restoration method. In order to see the influence of restoration on the stability of the nuclear matrix element, the variation of the nuclear matrix element with particle–particle strength parameter is computed within and without restoration. The calculated decay rates within restoration are compared with the schematic and shell model estimates.