Neutrino accompanied β±β±, β+/EC and EC/EC processes within single state dominance hypothesis

The systematic study of (anti)neutrino accompanied β±β± decays and β+/EC, EC/EC electron capture is performed under the assumption of single intermediate nuclear state dominance. The corresponding half-lives are evaluated both for transitions to the ground state as well as to the 0+ and 2+ excited states of final nucleus. It is stressed that the hypothesis of single state dominance can be confirmed or ruled out by the precision measurements of the differential characteristics of the 2νβ−β−-decays of 100Mo and 116Cd as well as β+/EC electron capture in 106Cd, 130Ba and 136Ce.