2-NEUTRINO DOUBLE-BETA-DECAY IN COUPLED QRPA WITH NEUTRON - PROTON PAIRING

Two-neutrino double-beta decay rates of Ca-46(20)26, Ca-48(20)-28, Ge- 76(32)44 and Se-82(34)48 are calculated with inclusion of neutron-prot on (np) pairing correlations in describing the ground states of initia l and final nuclei. Inclusion of np pairing correlations yields strong er bound nuclei as solutions of the HFB equation. Our results show tha t even in medium and medium-heavy nuclei, np pairing correlations redu ce the Gamow-Teller matrix elements compared to the results without np pairing. Further, the dependence of these matrix elements on the part icle-particle strength parameter g(pp) is reduced remarkably.