SUPPRESSION OF MATRIX ELEMENTS OF THE 2-NU-BETA-BETA DECAY BY THE COMPETITION BETWEEN SPIN-FLIP- AND NON-SPIN-FLIP- LIKE EXCITATIONS

摘要

The suppression of the nuclear matrix elements describing the two-neutrino nuclear double beta decay mode is studied in the context of a schematic model. The model is able to reproduce the features of extended calculations performed with realistic interactions, It is shown that the dominant mechanism leading to the suppression of the relevant nuclear matrix elements is the destructive interference between ''spin-flip''- and ''non-spin-flip''-like contributions to the transitions. Detailed results are shown for the case of the 2 nu beta beta ground-state-to-ground-state transition Ge-76 --> Se-76. [References: 20]