The CUORE experiment, a ton-scale cryogenic bolometer array, recently began operation at the Laboratori Nazionali del Gran Sasso in Italy. The array represents a significant advancement in this technology, and in this work we apply it for the first time to a high-sensitivity search for a lepton-number-violating process: ${}^{130}\mathrm{Te}$ neutrinoless double-beta decay. Examining a total ${\mathrm{TeO}}_2$ exposure of 86.3 kg yr, characterized by an effective energy resolution of $(7.7\pm 0.5)\mathrm{keV}$ FWHM and a background in the region of interest of $(0.014\pm 0.002)\mathrm{counts}/(\mathrm{keV}\mathrm{kg}\mathrm{yr})$, we find no evidence for neutrinoless double-beta decay. Including systematic uncertainties, we place a lower limit on the decay half-life of $T_{1/2}^{0\nu }({}^{130}\mathrm{Te})>1.3\times {10}^{25}\mathrm{yr}$ (90% C.L.); the median statistical sensitivity of this search is $7.0\times {10}^{24}\mathrm{yr}$. Combining this result with those of two earlier experiments, Cuoricino and CUORE-0, we find $T_{1/2}^{0\nu }({}^{130}\mathrm{Te})>1.5\times {10}^{25}\mathrm{yr}$ (90% C.L.), which is the most stringent limit to date on this decay. Interpreting this result as a limit on the effective Majorana neutrino mass, we find $m_{\beta \beta }<(110-520)\mathrm{meV}$, where the range reflects the nuclear matrix element estimates employed.

We report new results from the search for neutrinoless double-beta decay in ${}^{130}\hspace{0.17em}\mathrm{Te}$ with the CUORE detector. This search benefits from a fourfold increase in exposure, lower trigger thresholds, and analysis improvements relative to our previous results. We observe a background of $(1.38\pm 0.07)\times {10}^{-2}\mathrm{counts}/(\mathrm{keV}\mathrm{kg}\mathrm{yr})$) in the $0\nu \beta \beta$ decay region of interest and, with a total exposure of 372.5 kg yr, we attain a median exclusion sensitivity of $1.7\times {10}^{25}\mathrm{yr}$. We find no evidence for $0\nu \beta \beta$ decay and set a 90% credibility interval Bayesian lower limit of $3.2\times {10}^{25}\mathrm{yr}$ on the ${}^{130}\hspace{0.17em}\mathrm{Te}$ half-life for this process. In the hypothesis that $0\nu \beta \beta$ decay is mediated by light Majorana neutrinos, this results in an upper limit on the effective Majorana mass of 75–350 meV, depending on the nuclear matrix elements used.

The Cryogenic Underground Observatory for Rare Events (CUORE) is designed to search for neutrinoless double beta decay of $$^{130}$$ Te with an array of 98

CUPID-Mo is a bolometric experiment to search for neutrinoless double-beta decay ( $$0\nu \beta \beta $$0νββ ) of $$^{100}\hbox {Mo}$$100Mo . 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 $$^{100}\hbox {Mo}$$100Mo -enriched 0.2 kg $$\hbox {Li}_2\hbox {MoO}_4$$Li2MoO4 crystals operated as scintillating bolometers at $$\sim 20\hbox { mK}$$∼20mK . The $$\hbox {Li}_2\hbox {MoO}_4$$Li2MoO4 crystals are complemented by 20 thin Ge optical bolometers to reject $$\alpha $$α 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 $$\alpha $$α particles at a level much higher than 99.9% – with equally high acceptance for $$\gamma $$γ / $$\beta $$β events – in the region of interest for $$^{100}\hbox {Mo}$$100Mo $$0\nu \beta \beta $$0νββ . We present limits on the crystals’ radiopurity: $$\le 3~\mu \hbox {Bq/kg}$$≤3μBq/kg of $$^{226}\hbox {Ra}$$226Ra and $$\le 2~\mu \hbox {Bq/kg}$$≤2μBq/kg of $$^{232}\hbox {Th}$$232Th . We discuss the science reach of CUPID-Mo, which can set the most stringent half-life limit on the $$^{100}\hbox {Mo}$$100Mo $$0\nu \beta \beta $$0νββ 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 $$0\nu \beta \beta $$0νββ experiment.

We report on the measurement of the two-neutrino double-beta decay half-life of $$^{130}$$ Te with the CUORE-0 detector. From an exposure of 33.4