First Result on the Neutrinoless Double Beta Decay of ${}^{82}$Se with CUPID-0

Abstract

We report the result of the search for neutrinoless double beta decay of ${}^{82}$Se obtained with CUPID-0, the first large array of scintillating Zn${}^{82}$Se cryogenic calorimeters implementing particle identification. We observe no signal in a 1.83 kg yr ${}^{82}$Se exposure and we set the most stringent lower limit on the \onu ${}^{82}$Se half-life T${}_{1/2}^{0\nu }>$ 2.4$\times {10}^{24}$ yr (90\% credible interval), which corresponds to an effective Majorana neutrino mass m${}_{\beta \beta }<$ (376-770) meV depending on the nuclear matrix element calculations. The heat-light readout provides a powerful tool for the rejection of \al\ particles and allows to suppress the background in the region of interest down to (3.6${}_{-1.4}^{+1.9}$)$\times$10${}^{-3}$\ckky, an unprecedented level for this technique.