Explore the vast range of titles available.

A bstract Neutrinoless double-beta decay is a key process in particle physics. Its experimental investigation is the only viable method that can establish the Majorana nature of neutrinos, providing at the same time a sensitive inclusive test of lepton number violation. CROSS (Cryogenic Rare-event Observatory with Surface Sensitivity) aims at developing and testing a new bolometric technology to be applied to future large-scale experiments searching for neutrinoless double-beta decay of the promising nuclei 100 Mo and 130 Te. The limiting factor in large-scale bolometric searches for this rare process is the background induced by surface radioactive contamination, as shown by the results of the CUORE experiment. The basic concept of CROSS consists of rejecting this challenging background component by pulse-shape discrimination, assisted by a proper coating of the faces of the crystal containing the isotope of interest and serving as energy absorber of the bolometric detector. In this paper, we demonstrate that ultra-pure superconductive Al films deposited on the crystal surfaces act successfully as pulse-shape modifiers, both with fast and slow phonon sensors. Rejection factors higher than 99.9% of α surface radioactivity have been demonstrated in a series of prototypes based on crystals of Li 2 MoO 4 and TeO 2 . We have also shown that point-like energy depositions can be identified up to a distance of ∼ 1 mm from the coated surface. The present program envisions an intermediate experiment to be installed underground in the Canfranc laboratory (Spain) in a CROSS-dedicated facility. This experiment, comprising ∼ 3 × 10 25 nuclei of 100 Mo, will be a general test of the CROSS technology as well as a worldwide competitive search for neutrinoless double-beta decay, with sensitivity to the effective Majorana mass down to 70 meV in the most favorable conditions.

CUPID-Mo is a bolometric experiment to search for neutrinoless double-beta decay ( 0 ν β β ) of 100 Mo . 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 Mo -enriched 0.2 kg Li 2 MoO 4 crystals operated as scintillating bolometers at ∼ 20 mK . The Li 2 MoO 4 crystals are complemented by 20 thin Ge optical bolometers to reject 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 α particles at a level much higher than 99.9% – with equally high acceptance for γ / β events – in the region of interest for 100 Mo 0 ν β β . We present limits on the crystals’ radiopurity: ≤ 3 μ Bq/kg of 226 Ra and ≤ 2 μ Bq/kg of 232 Th . We discuss the science reach of CUPID-Mo, which can set the most stringent half-life limit on the 100 Mo 0 ν β β 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 ν β β experiment.

When sampling locations are known, the association between genetic and geographic distances can be tested by spatial autocorrelation or regression methods. These tests give some clues to the possible shape of the genetic landscape. Nevertheless, correlation analyses fail when attempting to identify where genetic barriers exist, namely, the areas where a given variable shows an abrupt rate of change. To this end, a computational geometry approach is more suitable because it provides the locations and the directions of barriers and because it can show where geographic patterns of two or more variables are similar. In this frame we have implemented Monmonier's (1973) maximum difference algorithm in a new software package to identify genetic barriers. To provide a more realistic representation of the barriers in a genetic landscape, we implemented in the software a significance test by means of bootstrap matrices analysis. As a result, the noise associated with genetic markers can be visualized on a geographic map and the areas where genetic barriers are more robust can be identified. Moreover, this multiple matrices approach can visualize the patterns of variation associated with different markers in the same overall picture. This improved Monmonier's method is highly reliable and can be applied to nongenetic data whenever sampling locations and a distance matrix between corresponding data are available.

We report the measurement of the two-neutrino double-beta ( 2 ν β β ) decay of 100 Mo to the ground state of 100 Ru using lithium molybdate ( Li 2 100 MoO 4 ) 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 (France). From a total exposure of 42.235 kg × day, the half-life of 100 Mo is determined to be T 1 / 2 2 ν = [ 7 . 12 - 0.14 + 0.18 ( stat . ) ± 0.10 ( syst . ) ] × 10 18  years. This is the most accurate determination of the 2 ν β β half-life of 100 Mo to date.

Neutrinoless double-beta decay is a key process in particle physics. Its experimental investigation is the only viable method that can establish the Majorana nature of neutrinos, providing at the same time a sensitive inclusive test of lepton number violation. CROSS (Cryogenic Rare-event Observatory with Surface Sensitivity) aims at developing and testing a new bolometric technology to be applied to future large-scale experiments searching for neutrinoless double-beta decay of the promising nuclei¹⁰⁰ Mo and¹³⁰ Te. The limiting factor in large-scale bolometric searches for this rare process is the background induced by surface radioactive contamination, as shown by the results of the CUORE experiment. The basic concept of CROSS consists of rejecting this challenging background component by pulse-shape discrimination, assisted by a proper coating of the faces of the crystal containing the isotope of interest and serving as energy absorber of the bolometric detector. In this paper, we demonstrate that ultra-pure superconductive Al films deposited on the crystal surfaces act successfully as pulse-shape modifiers, both with fast and slow phonon sensors. Rejection factors higher than 99.9% of α surface radioactivity have been demonstrated in a series of prototypes based on crystals of Li ₂ MoO ₄and TeO ₂ . We have also shown that point-like energy depositions can be identified up to a distance of ∼ 1 mm from the coated surface. The present program envisions an intermediate experiment to be installed underground in the Canfranc laboratory (Spain) in a CROSS-dedicated facility. This experiment, comprising ∼ 3×10 ²⁵nuclei of¹⁰⁰ Mo, will be a general test of the CROSS technology as well as a worldwide competitive search for neutrinoless double-beta decay, with sensitivity to the effective Majorana mass down to 70 meV in the most favorable conditions.[graphic not available: see fulltext]

We report the measurement of the two-neutrino double-beta (2νββ) decay of ¹⁰⁰Mo to the ground state of ¹⁰⁰Ru 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×d, the half-life of ¹⁰⁰Mo is determined to be T_(1/2)^(2ν)=[7.12^(+0.18)_(-0.14) \\mathrm{(stat.)}{±}{0}.10 \\mathrm{(syst.)}{]}{×}10¹⁸ years. This is the most accurate determination of the 2νββ half-life of ¹⁰⁰Mo to date. We also confirm, with the statistical significance of >3σ, that the single-state dominance model of the 2νββ decay of ¹⁰⁰Mo is favored over the high-state dominance model.

We report the measurement of the two-neutrino double-beta ($$2\\nu \\beta \\beta $$2 ν β β ) decay of$$^{100}$$100 Mo to the ground state of$$^{100}$$100 Ru using lithium molybdate ($$\\hbox {Li}_2^{\\;\\;100}\\hbox {MoO}_4$$Li 2 100 MoO 4 ) 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 (France). From a total exposure of 42.235 kg$$\\times $$× day, the half-life of$$^{100}$$100 Mo is determined to be$$T_{1/2}^{2\\nu }=[7.12^{+0.18}_{-0.14}\\,\\mathrm {(stat.)}\\pm 0.10\\,\\mathrm {(syst.)}]\\times 10^{18}$$T 1 / 2 2 ν = [ 7 . 12 - 0.14 + 0.18 ( stat . ) ± 0.10 ( syst . ) ] × 10 18  years. This is the most accurate determination of the$$2\\nu \\beta \\beta $$2 ν β β half-life of$$^{100}$$100 Mo to date.

Abstract We report the measurement of the two-neutrino double-beta ( 2ν β β 2νββ ) decay of¹⁰⁰100 Mo to the ground state of¹⁰⁰100 Ru using lithium molybdate ( \\hbox Li₂¹⁰⁰\\hbox MoO₄Li2100MoO4 ) 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 (France). From a total exposure of 42.235 kg × × day, the half-life of¹⁰⁰100 Mo is determined to beT_(1/2)^(2ν)=[7.12^(+0.18)_(-0.14) \\mathrm (stat.)± 0.10 \\mathrm (syst.)]× 10¹⁸T1/22ν=[7.12-0.14+0.18(stat.)±0.10(syst.)]×1018  years. This is the most accurate determination of the2ν β β 2νββ half-life of¹⁰⁰100 Mo to date.

We report the measurement of the two-neutrino double-beta ( 2ν β β ) decay of¹⁰⁰ Mo to the ground state of¹⁰⁰ Ru using lithium molybdate ( \\hbox Li₂¹⁰⁰\\hbox MoO₄ ) 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 (France). From a total exposure of 42.235 kg × day, the half-life of¹⁰⁰ Mo is determined to beT_(1/2)^(2ν)=[7.12^(+0.18)_(-0.14) \\mathrm (stat.)± 0.10 \\mathrm (syst.)]× 10¹⁸  years. This is the most accurate determination of the2ν β β half-life of¹⁰⁰ Mo to date.

The CROSS experiment is proposing to use a new technology of surface sensitive bolometers for low-background neutrinoless double beta decay searches. Efficient rejection of surface α and β events will allow to reach background in the region of interest below than 10 −4 cnts/keV/kg/yr. The isotopes of interest, which are 130 Te and 100 Mo, are investigated with TeO 2 and Li 2 MoO 4 bolometers. The surface sensitivity is achieved thanks to the evaporation of thin metallic film on the crystal surface that modifies the pulse shape of near-surface events. An investigation of various pulse shape parameters was performed. The analysis shows that one of the best parameters for discrimination is the integrated area of the raw signal both for TeO 2 and Li 2 MoO 4 with Pd-Al (10 nm - 100 nm) bi-layer.