Deformation effects on the Gamow-Teller strength distributions in the double-β decay partners 76Ge and 76Se

A theoretical approach based on a deformed quasiparticle random phase approximation built on a Skyrme self-consistent mean field is used to describe the recent measurements of the Gamow-Teller GT(-) strength distribution extracted from the charge-exchange reaction Ge-76(He-3, t)As-76 with high energy resolution. The same analysis is made to describe the Gamow-Teller GT(+) strength distribution measured in the Se-76(d, He-2)As-76 reaction. Combining these two branches, the nuclear matrix element for the two-neutrino double-beta decay process is evaluated and compared to experiment. The role of the nuclear deformation on those processes is emphasized and analyzed.