Study of the double beta decay of 70⩽A⩽100 nuclei within the RQRPA and the self-consistent BCS + RQRPA formalisms

We have used a newly presented self-consistent version of the BCS+RQRPA method for a nucleus-by-nucleus study of the double beta decay in the medium-heavy region. The results have been compared to the previously used approaches, namely the QRPA and the RQRPA approximations. We have shown that inclusion of the quasiparticle correlations at the BCS level reduces ground state correlations in the particle–particle channel of the proton–neutron interaction, resulting in the systematic reduction of the double beta decay matrix elements.