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

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