Final Result of CUPID-0 Phase-I in the Search for the ^{82}Se Neutrinoless Double-β Decay

• Published in: Physical review letters Vol. 123; no. 3; p. 032501
• Main Authors: 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, Cruciani, A, Dafinei, I, Di Domizio, S, Ferroni, F, Gironi, L, Giuliani, A, Gorla, P, Gotti, C, Keppel, G, Martinez, M, Nagorny, S, Nastasi, M, Nisi, S, Nones, C, Orlandi, D, Pagnanini, L, Pallavicini, M, Pattavina, L, Pavan, M, Pessina, G, Pettinacci, V, Pirro, S, Pozzi, S, Previtali, E, Puiu, A, Rusconi, C, Schäffner, K, Tomei, C, Vignati, M, Zolotarova, A S
• Format: Journal Article
• Language: English
• Published: United States 19.07.2019
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.123.032501

CUPID-0 is the first pilot experiment of CUPID, a next-generation project for the measurement of neutrinoless double beta decay (0νDBD) with scintillating bolometers. The detector, consisting of 24 enriched and 2 natural ZnSe crystals, has been taking data at Laboratori Nazionali del Gran Sasso from June 2017 to December 2018, collecting a ^{82}Se exposure of 5.29  kg×yr. In this Letter we present the phase-I results in the search for 0νDBD. We demonstrate that the technology implemented by CUPID-0 allows us to reach the lowest background for calorimetric experiments: (3.5_{-0.9}^{+1.0})×10^{-3}  counts/(keV kg yr). Monitoring 3.88×10^{25} ^{82}Se nuclei×yr we reach a 90% credible interval median sensitivity of T_{1/2}^{0ν}>5.0×10^{24}  yr and set the most stringent limit on the half-life of ^{82}Se 0νDBD: T_{1/2}^{0ν}>3.5×10^{24}  yr (90% credible interval), corresponding to m_{ββ}<(311-638)  meV depending on the nuclear matrix element calculations.