Theoretical investigation of the double-β processes in 96Ru

The two-neutrino (2 nu 2 beta) and neutrinoless (0 nu 2 beta) double-beta decays of Ru-96 are investigated for the transitions to the ground state, 0(gs)(+), and 0(+) and 2(+) excited states in Mo-96 by using the quasiparticle random-phase approximation combinedwith the multiple-commutator model. G-matrix-based nuclear forces are used in realistic single-particle model spaces. All the possible channels, beta(+) beta(+), beta(+) EC, and ECEC, are discussed for both the 2 nu 2 beta and 0 nu 2 beta decays. The associated half-lives are computed, in particular the one corresponding to the resonant neutrinoless double electron capture (R0 nu ECEC) transition to the 2.712.68-MeV nuclear state in Mo-96. This work represents the most complete theoretical investigation of the double-beta-decay properties of Ru-96 thus far.