Two-neutrino positron double-beta decay of

The two-neutrino positron double-beta decay of 106Cd 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 106Cd and 106Pd 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 2ν and the half-life T 1/2 2ν 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 2ν