Two-neutrino positron double-beta decay of 106Cd for the 0+→0+ transition

The two-neutrino positron double-beta decay of Cd-106 for the 0(+) --> 0(+) transition has been studied in the Hartree-Fock-Bogoliubov model in conjunction with the summation method. In the first step, the reliability of the intrinsic wave functions of Cd-106 and Pd-106 nuclei has been tested by comparing the theoretically calculated results for yrast spectra, reduced B(E2:0(+) --> 2(+)) transition probabilities, quadrupole moments Q(2(+)) and gyromagnetic factors g(2(+)) with the available experimental data. In the second step, the nuclear transition matrix element M-2nu and the half-life T-1/2(2nu) for the 0(+) --> 0(+) transition have been calculated with these wave functions. Moreover, we have studied the effect of deformation on the nuclear transition matrix element M-2nu.