Evidence of Single State Dominance in the Two-Neutrino Double- ? Decay of Se 82 with CUPID-0
We report on the measurement of the two-neutrino double-? decay of Se82 performed for the first time with cryogenic calorimeters, in the framework of the CUPID-0 experiment. With an exposure of 9.95 kg yr of ZnSe82, we determine the two-neutrino double-? decay half-life of Se82 with an unprecedented precision level, T1/22?=[8.60±0.03(stat) -0.13+0.19(syst)]×1019 yr.