Final results on the $$0\nu \beta \beta $$ decay half-life limit of $$^{100}$$ Mo from the CUPID-Mo experiment
C. Augier (Univ Lyon, Université Lyon 1, CNRS/IN2P3, IP2I-Lyon, Villeurbanne, 69622, France); A. Barabash (National Research Centre Kurchatov Institute, Institute of Theoretical and Experimental Physics, Moscow, 117218, Russia); F. Bellini (INFN, Sezione di Roma, P.le Aldo Moro 2, Rome, 00185, Italy, Dipartimento di Fisica, Sapienza Università di Roma, P.le Aldo Moro 2, Rome, 00185, Italy); G. Benato (IRFU, CEA, Université Paris-Saclay, Gif-sur-Yvette, 91191, France, INFN, Laboratori Nazionali del Gran Sasso, Assergi, AQ, 67100, Italy); M. Beretta (Department of Physics, University of California, Berkeley, CA, 94720, USA); et al - Show all 80 authors
The CUPID-Mo experiment to search for 0 $$\nu \beta \beta $$ decay in $$^{100}$$ Mo has been recently completed after about 1.5 years of operation at Laboratoire Souterrain de Modane (France). It served as a demonstrator for CUPID, a next generation 0 $$\nu \beta \beta $$ decay experiment. CUPID-Mo was comprised of 20 enriched $$\hbox {Li}_{{2}}$$ $$^{100}$$ $$\hbox {MoO}_4$$ scintillating calorimeters, each with a mass of $$\sim 0.2$$ kg, operated at $$\sim 20$$ mK. We present here the final analysis with the full exposure of CUPID-Mo ( $$^{100}$$ Mo exposure of 1.47 $$\hbox {kg} \times \hbox {year}$$ ) used to search for lepton number violation via 0 $$\nu \beta \beta $$ decay. We report on various analysis improvements since the previous result on a subset of data, reprocessing all data with these new techniques. We observe zero events in the region of interest and set a new limit on the $$^{100}$$ Mo 0 $$\nu \beta \beta $$ decay half-life of $$T_{1/2}^{0\nu }$$ $$> {1.8}\times 10^{24}$$ year (stat. + syst.) at 90% CI. Under the light Majorana neutrino exchange mechanism this corresponds to an effective Majorana neutrino mass of $$\left<m_{\beta \beta }\right>$$ $$<~{(0.28{-}0.49)} $$ eV, dependent upon the nuclear matrix element utilized.
