First Result on the Neutrinoless Double-$\beta$ Decay of $^{82}Se$ with CUPID-0
Résumé
We report the result of the search for neutrinoless double beta decay of Se82 obtained with CUPID-0, the first large array of scintillating ZnSe82 cryogenic calorimeters implementing particle identification. We observe no signal in a 1.83 kg yr Se82 exposure, and we set the most stringent lower limit on the 0νββ Se82 half-life T1/20ν>2.4×1024 yr (90% credible interval), which corresponds to an effective Majorana neutrino mass mββ<(376–770) meV depending on the nuclear matrix element calculations. The heat-light readout provides a powerful tool for the rejection of α particles and allows us to suppress the background in the region of interest down to (3.6-1.4+1.9)×10-3 counts/(keV kg yr), an unprecedented level for this technique.