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Abstract CUPID, the CUORE Upgrade with Particle Identification, is a next-generation experiment to search for neutrinoless double beta decay ($$0\mathrm {\nu \beta \beta }$$ $0\nu \beta \beta$) and other rare events using enriched Li$$_{2}$$ $_2^{}$$$^{100}$$ $_{}^{100}$MoO$$_{4}$$ $_4^{}$scintillating bolometers. It will be hosted by the CUORE cryostat located at the Laboratori Nazionali del Gran Sasso in Italy. The main physics goal of CUPID is to search for$$0\mathrm {\nu \beta \beta }$$ $0\nu \beta \beta$of$$^{100}$$ $_{}^{100}$Mo with a discovery sensitivity covering the full neutrino mass regime in the inverted ordering scenario, as well as the portion of the normal ordering regime with lightest neutrino mass larger than 10 meV. With a conservative background index of 10$$^{-4}$$ $_{}^{-4}$ cts$$/($$ $/($keV$$\cdot $$ $·$kg$$\cdot $$ $·$yr$$)$$ $)$, 240 kg isotope mass, 5 keV FWHM energy resolution at 3 MeV and 10 live-years of data taking, CUPID will have a 90% C.L. half-life exclusion sensitivity of$$1.8\cdot 10^{27}$$ $1.8·{10}^{27}$ yr, corresponding to an effective Majorana neutrino mass ($$m_{\beta \beta }$$ $m_{\beta \beta }$) sensitivity of 9–15 meV, and a$$3\sigma $$ $3\sigma$discovery sensitivity of$$1\cdot 10^{27}$$ $1·{10}^{27}$ yr, corresponding to an$$m_{\beta \beta }$$ $m_{\beta \beta }$range of 12–21 meV. 

The Cryogenic Underground Observatory for Rare Events (CUORE) is a detector array comprised by 988 $5\mathrm{cm}\times 5\mathrm{cm}\times 5\mathrm{cm}$ ${\mathrm{TeO}}_2$crystals held below 20 mK, primarily searching for neutrinoless double-beta decay in ${}^{130}\mathrm{Te}$. Unprecedented in size among cryogenic calorimetric experiments, CUORE provides a promising setting for the study of exotic throughgoing particles. Using the first tonne year of CUORE’s exposure, we perform a search for hypothesized (FCPs), which are well-motivated by various standard model extensions and would have suppressed interactions with matter. Across the searched range of charges $e/24-e/2$no excess of FCP candidate tracks is observed over background, setting leading limits on the underground FCP flux with charges $e/24-e/5$at 90% confidence level. Using the low background environment and segmented geometry of CUORE, we establish the sensitivity of tonne-scale subkelvin detectors to diverse signatures of new physics. Published by the American Physical Society2024 

The anionic products following (H + H + ) abstraction from o -, m -, and p -methylphenol (cresol) are investigated using flowing afterglow-selected ion flow tube (FA-SIFT) mass spectrometry and anion photoelectron spectroscopy (PES). The PES of the multiple anion isomers formed in this reaction are reported, including those for the most abundant isomers, o -, m - and p -methylenephenoxide distonic radical anions. The electron affinity (EA) of the ground triplet electronic state of neutral m -methylenephenoxyl diradical was measured to be 2.227 ± 0.008 eV. However, the ground singlet electronic states of o - and p -methylenephenoxyl were found to be significantly stabilized by their resonance forms as a substituted cyclohexadienone, resulting in measured EAs of 1.217 ± 0.012 and 1.096 ± 0.007 eV, respectively. Upon electron photodetachment, the resulting neutral molecules were shown to have Franck–Condon active ring distortion vibrational modes with measured frequencies of 570 ± 180 and 450 ± 80 cm −1 for the ortho and para isomers, respectively. Photodetachment to excited electronic states was also investigated for all isomers, where similar vibrational modes were found to be Franck–Condon active, and singlet–triplet splittings are reported. The thermochemistry of these molecules was investigated using FA-SIFT combined with the acid bracketing technique to yield values of 341.4 ± 4.3, 349.1 ± 3.0, and 341.4 ± 4.3 kcal mol −1 for the o -, m -, and p -methylenephenol radicals, respectively. Construction of a thermodynamic cycle allowed for an experimental determination of the bond dissociation energy of the O–H bond of m -methylenephenol radical to be 86 ± 4 kcal mol −1 , while this bond is significantly weaker for the ortho and para isomers at 55 ± 5 and 52 ± 5 kcal mol −1 , respectively. Additional EAs and vibrational frequencies are reported for several methylphenyloxyl diradical isomers, the negative ions of which are also formed by the reaction of cresol with O − . 

Abstract The Cryogenic Underground Observatory for Rare Events (CUORE) is the most sensitive experiment searching for neutrinoless double-beta decay (0 νββ ) in 130 Te. CUORE uses a cryogenic array of 988 TeO 2 calorimeters operated at ∼10 mK with a total mass of 741 kg. To further increase the sensitivity, the detector response must be well understood. Here, we present a non-linear thermal model for the CUORE experiment on a detector-by-detector basis. We have examined both equilibrium and dynamic electro-thermal models of detectors by numerically fitting non-linear differential equations to the detector data of a subset of CUORE channels which are well characterized and representative of all channels. We demonstrate that the hot-electron effect and electric-field dependence of resistance in NTD-Ge thermistors alone are inadequate to describe our detectors' energy-dependent pulse shapes. We introduce an empirical second-order correction factor in the exponential temperature dependence of the thermistor, which produces excellent agreement with energy-dependent pulse shape data up to 6 MeV. We also present a noise analysis using the fitted thermal parameters and show that the intrinsic thermal noise is negligible compared to the observed noise for our detectors. 

Abstract An array of twelve 0.28 kg lithium molybdate (LMO) low-temperature bolometers equipped with 16 bolometric Ge light detectors, aiming at optimization of detector structure for CROSS and CUPID double-beta decay experiments, was constructed and tested in a low-background pulse-tube-based cryostat at the Canfranc underground laboratory in Spain. Performance of the scintillating bolometers was studied depending on the size of phonon NTD-Ge sensors glued to both LMO and Ge absorbers, shape of the Ge light detectors (circular vs. square, from two suppliers), in different light collection conditions (with and without reflector, with aluminum coated LMO crystal surface). The scintillating bolometer array was operated over 8 months in the low-background conditions that allowed to probe a very low, μBq/kg, level of the LMO crystals radioactive contamination by 228 Th and 226 Ra. 

Abstract CUPID is a next-generation bolometric experiment aiming at searching for neutrinoless double-beta decay with ∼250 kg of isotopic mass of 100 Mo. It will operate at ∼10 mK in a cryostat currently hosting a similar-scale bolometric array for the CUORE experiment at the Gran Sasso National Laboratory (Italy). CUPID will be based on large-volume scintillating bolometers consisting of 100 Mo-enriched Li 2 MoO 4 crystals, facing thin Ge-wafer-based bolometric light detectors. In the CUPID design, the detector structure is novel and needs to be validated. In particular, the CUORE cryostat presents a high level of mechanical vibrations due to the use of pulse tubes and the effect of vibrations on the detector performance must be investigated. In this paper we report the first test of the CUPID-design bolometric light detectors with NTD-Ge sensors in a dilution refrigerator equipped with a pulse tube in an above-ground lab. Light detectors are characterized in terms of sensitivity, energy resolution, pulse time constants, and noise power spectrum. Despite the challenging noisy environment due to pulse-tube-induced vibrations, we demonstrate that all the four tested light detectors comply with the CUPID goal in terms of intrinsic energy resolution of 100 eV RMS baseline noise. Indeed, we have measured 70–90 eV RMS for the four devices, which show an excellent reproducibility. We have also obtained high energy resolutions at the 356 keV line from a 133 Ba source, as good as Ge semiconductor γ detectors in this energy range.