Evidence of Single State Dominance in the Two-Neutrino Double-β Decay of 82Se with CUPID-0
Azzolini, O.; Beeman, J. W.; Bellini, F.; Beretta, M.; Biassoni, M.; Brofferio, C.; Bucci, C.; Capelli, S.; Cardani, L.; Carniti, P.; Casali, N.; Chiesa, D.; Clemenza, M.; Cremonesi, O. et al. (2019). Evidence of Single State Dominance in the Two-Neutrino Double-β Decay of 82Se with CUPID-0. Physical Review Letters, 123 (26), 262501. DOI: 10.1103/PhysRevLett.123.262501
Published inPhysical Review Letters
Nisi, S. |
Puiu, A. |
© 2019 American Physical Society
We report on the measurement of the two-neutrino double-β decay of 82Se performed for the first time with cryogenic calorimeters, inthe framework of theCUPID-0experiment. With anexposureof 9.95 kg yr of Zn82Se, we determine the two-neutrino double-β decay half-life of 82Se with an unprecedentedprecision level, T2ν½ = [8.60 0.03(stat)þ0.19 −0.13(syst)]× 1019 yr. The very high signal-to-background ratio, along with the detailed reconstruction of the background sources allowed us to identify the single state dominance as the underlying mechanism of such a process, demonstrating that the higher state dominance hypothesis is disfavored at the level of 5.5σ.