Precise measurement of $2\hat{I}½{\hat{I}}^2{\hat{I}}^2$ decay of ${}^{100}$Mo with the CUPID-Mo detection technology

Abstract

We report the measurement of the two-neutrino double-beta ($2\hat{I}½{\hat{I}}^2{\hat{I}}^2$) decay of ${}^{100}$Mo to the ground state of ${}^{100}$Ru using lithium molybdate (\crystal) scintillating bolometers. The detectors were developed for the CUPID-Mo program and operated at the EDELWEISS-III low background facility in the Modane underground laboratory. From a total exposure of $42.235$ kg$\times$d, the half-life of ${}^{100}$Mo is determined to be $T_{1/2}^{2\hat{I}½}=[7.12_{-0.14}^{+0.18}(stat.)\pm 0.10(syst.)]\times 10^{18}$ years. This is the most accurate determination of the $2\hat{I}½{\hat{I}}^2{\hat{I}}^2$ half-life of ${}^{100}$Mo to date. We also confirm, with the statistical significance of $>3\ddot{I}ƒ$, that the single-state dominance model of the $2\hat{I}½{\hat{I}}^2{\hat{I}}^2$ decay of ${}^{100}$Mo is favored over the high-state dominance model.

11 pages, 6 figures, 4 tables