New Limit for Neutrinoless Double-Beta Decay of ${}^{100}$Mo from the CUPID-Mo Experiment

Abstract

The CUPID-Mo experiment at the Laboratoire Souterrain de Modane (France) is a demonstrator for CUPID, the next-generation ton-scale cryogenic $0\hat{I}½{\hat{I}}^2{\hat{I}}^2$ experiment. It consists of a 4.2 kg array of 20 enriched Li${}_2$${}^{100}$MoO${}_4$ scintillating bolometers to search for the lepton number violating process of $0\hat{I}½{\hat{I}}^2{\hat{I}}^2$ decay in ${}^{100}$Mo. With more than one year of operation (2.16 kg$\times$yr of physics data), no event in the region of interest and hence no evidence for $0\hat{I}½{\hat{I}}^2{\hat{I}}^2$ is observed. We report a new limit on the half-life of $0\hat{I}½{\hat{I}}^2{\hat{I}}^2$ decay in ${}^{100}$Mo of $T_{1/2}>1.5\times 10^{24}$yr at 90 % C.I. The limit corresponds to an effective Majorana neutrino mass $⟨m_{{\hat{I}}^2{\hat{I}}^2}⟩$ $<$ (0.31--0.54)eV, dependent on the nuclear matrix element in the light Majorana neutrino exchange interpretation.