Description
The CUPID-Mo experiment demonstrated the performance of cryogenic scintillating Li$_2^{100}$MoO$_4$ calorimeters for the use in the CUPID (CUORE Upgrade with Particle IDentification) neutrinoless double beta decay ($0\nu\beta\beta$) search. It consisted of an array of twenty detector modules with $\sim$200-g detectors and Ge wafer based light detectors enabling particle identification. It was operated at the Laboratoire Souterrain de Modane (France) from 2018 to 2020. In this work, we demonstrate the applicability of the experimental design towards a search for two-neutrino and neutrinoless double beta decays of $^{100}$Mo to the 0$_1^+$ and $2_1^+$ excited states of $^{100}$Ru. We present results for the measured half-life of the $2\nu\beta\beta$ decay to the 0$_1^+$ state using the full CUPID-Mo exposure (2.71 kg-yr of Li$_2^{100}$MoO$_4$). The acquired statistics allows us to make the first comparison of the single state (SSD) and higher state (HSD) $2\nu\beta\beta$ decay models for the decay to the $0_1^+$ excited state of $^{100}$Ru demonstrating the potential of the technique for future experiments. We also present the analysis of the neutrinoless decay mode to the $2_1^+$ and the $0_1^+$ states. These results are expected to be the most stringent constraints on these processes in $^{100}$Mo to date.
| Collaboration | CUPID-Mo |
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