The CUPID-Mo experiment for neutrinoless double-beta decay: performance and prospects

CUPID-Mo is a bolometric experiment to search for neutrinoless double-beta decay (0 nu beta beta) of Mo-100. In this article, we detail the CUPID-Mo detector concept, assembly and installation in the Modane underground laboratory, providing results from the first datasets. The CUPID-Mo detector consists of an array of 20 Mo-100-enriched 0.2 kgLi(2)MoO(4) crystals operated as scintillating bolometers at similar to 20 mK. The Li2MoO4 crystals are complemented by 20 thin Ge optical bolometers to reject alpha events by the simultaneous detection of heat and scintillation light. We observe a good detector uniformity and an excellent energy resolution of 5.3 keV (6.5 keV) FWHM at 2615 keV, in calibration (physics) data. Light collection ensures the rejection of a particles at a level much higher than 99.9% - with equally high acceptance for gamma/beta events - in the region of interest for Mo-100 0 nu beta beta. We present limits on the crystals' radiopurity: <= 3 mu Bq/kg of Ra-226 and <= 2 mu Bq/kg of Th-232. We discuss the science reach of CUPID-Mo, which can set the most stringent half-life limit on the Mo-100 0 nu beta beta decay in half-a-year's livetime. The achieved results show that CUPID-Mo is a successful demonstrator of the technology developed by the LUMINEU project and subsequently selected for the CUPID experiment, a proposed follow-up of CUORE, the currently running first tonne-scale bolometric 0 nu beta beta experiment.