arXiv subjects

C. Nones

Publications and source records attributed to C. Nones.

At least 91 records · Page 5Linked to original sources

arXiv2019

The $0\nu2β$-decay CROSS experiment: preliminary results and prospects

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 $\sim 1$ 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 $\sim 3\times 10^{25}$ 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.

nucl-ex↗

arXiv2019

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 ($0νββ$) of $^{100}$Mo. In this article, we detail the CUPID-Mo detector concept, assembly, installation in the underground laboratory in Modane in 2018, and provide results from the first datasets. The demonstrator consists of an array of 20 scintillating bolometers comprised of $^{100}$Mo-enriched 0.2 kg Li$_2$MoO$_4$ crystals. The detectors are complemented by 20 thin cryogenic Ge bolometers acting as light detectors to distinguish $α$ from $γ$/$β$ events by the detection of both heat and scintillation light signals. We observe good detector uniformity, facilitating the operation of a large detector array as well as excellent energy resolution of 5.3 keV (6.5 keV) FWHM at 2615 keV, in calibration (physics) data. Based on the observed energy resolutions and light yields a separation of $α$ particles at much better than 99.9\% with equally high acceptance for $γ$/$β$ events is expected for events in the region of interest for $^{100}$Mo $0νββ$. We present limits on the crystals' radiopurity ($\leq$3 $μ$Bq/kg of $^{226}$Ra and $\leq$2 $μ$Bq/kg of $^{232}$Th). Based on these initial results we also discuss a sensitivity study for the science reach of the CUPID-Mo experiment, in particular, the ability to set the most stringent half-life limit on the $^{100}$Mo $0νββ$ decay after half a year of livetime. The achieved results show that CUPID-Mo is a successful demonstrator of the technology - developed in the framework of the LUMINEU project - selected for the CUPID experiment, a proposed follow-up of CUORE, the currently running first tonne-scale cryogenic $0νββ$ experiment.

physics.ins-det↗

arXiv2019

First results on sub-GeV spin-dependent dark matter interactions with $^{7}$Li

In this work, we want to highlight the potential of lithium as a target for spin-dependent dark matter search in cryogenic experiments, with a special focus on the low-mass region of the parameter space. We operated a prototype detector module based on a Li$_2$MoO$_4$ target crystal in an above-ground laboratory. Despite the high background environment, the detector sets competitive limits on spin-dependent interactions of dark matter particles with protons and neutrons for masses between 0.8 GeV/c$^2$ and 1.5 GeV/c$^2$.

astro-ph.IM↗

arXiv2019

First test of a $\mathrm{CdMoO_4}$ scintillating bolometer for neutrinoless double beta decay experiments with $\mathrm{{}^{116}Cd}$ and $\mathrm{{}^{100}Mo}$ nuclides

A large cylindrical cadmium molybdate crystal with natural isotopic abundance has been used to fabricate a scintillating bolometer. The measurement was performed above ground at milli-Kelvin temperature, with simultaneous readout of the heat and the scintillation light. The energy resolution as FWHM has achieved from 5 keV (at 238 keV) to 13 keV (at 2615 keV). We present the results of the $α$ versus $β$/$γ$ events discrimination. The low internal trace contamination of the $\mathrm{CdMoO_4}$ crystal was evaluated as well. The detector performance with preliminary positive indications proves that cadmium molybdate crystal is a promising absorber for neutrinoless double beta decay scintillating bolometric experiments with $\mathrm{{}^{116}Cd}$ and $\mathrm{{}^{100}Mo}$ nuclides in the next-generation technique.

physics.ins-det↗

arXiv2019

Background Model of the CUPID-0 Experiment

CUPID-0 is the first large mass array of enriched Zn$^{82}$Se scintillating low temperature calorimeters, operated at LNGS since 2017. During its first scientific runs, CUPID-0 collected an exposure of 9.95 kg yr. Thanks to the excellent rejection of $α$ particles, we attained the lowest background ever measured with thermal detectors in the energy region where we search for the signature of $^{82}$Se neutrinoless double beta decay. In this work we develop a model to reconstruct the CUPID-0 background over the whole energy range of experimental data. We identify the background sources exploiting their distinctive signatures and we assess their extremely low contribution (down to $\sim10^{-4}$ counts/(keV kg yr)) in the region of interest for $^{82}$Se neutrinoless double beta decay search. This result represents a crucial step towards the comprehension of the background in experiments based on scintillating calorimeters and in next generation projects such as CUPID.

nucl-ex↗

arXiv2019

Final result of CUPID-0 phase-I in the search for the $^{82}$Se Neutrinoless Double Beta Decay

CUPID-0 is the first pilot experiment of CUPID, a next-generation project for the measurement of neutrinoless double beta decay (0$ν$DBD) with scintillating bolometers. The detector, consisting of 24 enriched and 2 natural ZnSe crystals, has been taking data at Laboratori Nazionali del Gran Sasso from June 2017 to December 2018, collecting a $^{82}$Se exposure of 5.29 kg$\times$yr. In this paper we present the phase-I results in the search for 0$ν$DBD. We demonstrate that the technology implemented by CUPID-0 allows us to reach the lowest background for calorimetric experiments: $(3.5^{+1.0}_{-0.9})\times10^{-3}$ counts/(keV kg yr). Monitoring 3.88$\times$10$^{25}$ $^{82}$Se nuclei$\times$yr we reach a 90% credible interval median sensitivity of $\rm{T}^{0ν}_{1/2}>5.0\times10^{24} \rm{yr}$ and set the most stringent limit on the half-life of $^{82}$Se 0$ν$DBD : $\rm{T}^{0ν}_{1/2}>3.5\times10^{24} \rm{yr}$ (90% credible interval), corresponding to m$_{ββ} <$ (311-638) meV depending on the nuclear matrix element calculations.

nucl-ex↗

arXiv2019

Physics potential of the International Axion Observatory (IAXO)

We review the physics potential of a next generation search for solar axions: the International Axion Observatory (IAXO). Endowed with a sensitivity to discover axion-like particles (ALPs) with a coupling to photons as small as $g_{aγ}\sim 10^{-12}$ GeV$^{-1}$, or to electrons $g_{ae}\sim$10$^{-13}$, IAXO has the potential to find the QCD axion in the 1 meV$\sim$1 eV mass range where it solves the strong CP problem, can account for the cold dark matter of the Universe and be responsible for the anomalous cooling observed in a number of stellar systems. At the same time, IAXO will have enough sensitivity to detect lower mass axions invoked to explain: 1) the origin of the anomalous "transparency" of the Universe to gamma-rays, 2) the observed soft X-ray excess from galaxy clusters or 3) some inflationary models. In addition, we review string theory axions with parameters accessible by IAXO and discuss their potential role in cosmology as Dark Matter and Dark Radiation as well as their connections to the above mentioned conundrums.

hep-ph↗

arXiv2019

Exploring CEvNS with NUCLEUS at the Chooz Nuclear Power Plant

Coherent elastic neutrino-nucleus scattering (CE$ν$NS) offers a unique way to study neutrino properties and to search for new physics beyond the Standard Model. Nuclear reactors are promising sources to explore this process at low energies since they deliver large fluxes of (anti-)neutrinos with typical energies of a few MeV. In this paper, a new-generation experiment to study CE$ν$NS is described. The NUCLEUS experiment will use cryogenic detectors which feature an unprecedentedly low energy threshold and a time response fast enough to be operated in above-ground conditions. Both sensitivity to low-energy nuclear recoils and a high event rate tolerance are stringent requirements to measure CE$ν$NS of reactor antineutrinos. A new experimental site, denoted the Very-Near-Site (VNS) at the Chooz nuclear power plant in France is described. The VNS is located between the two 4.25 GW$_{\mathrm{th}}$ reactor cores and matches the requirements of NUCLEUS. First results of on-site measurements of neutron and muon backgrounds, the expected dominant background contributions, are given. In this paper a preliminary experimental setup with dedicated active and passive background reduction techniques is presented. Furthermore, the feasibility to operate the NUCLEUS detectors in coincidence with an active muon-veto at shallow overburden is studied. The paper concludes with a sensitivity study pointing out the promising physics potential of NUCLEUS at the Chooz nuclear power plant.

physics.ins-det↗

arXiv2019

Results of CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) at the Laboratori Nazionali del Gran Sasso, Italy, is the world's largest bolometric experiment. The detector consists of an array of 988 TeO2 crystals, for a total mass of 742 kg. CUORE is presently in data taking, searching for the neutrinoless double beta decay of 130 Te. CUORE is operational since the spring of 2017. The initial science run already allowed to provide the most stringent limit on the neutrinoless double beta decay half-life of 130Te, and to perform the most precise measurement of the two-neutrino double beta decay half-life. Up to date, we have more than doubled the collected exposure. In this talk, we presenteded the most recent results and discuss the present status of the CUORE experiment.

nucl-ex↗

arXiv2019

Searching for low-mass dark matter particles with a massive Ge bolometer operated above-ground

The EDELWEISS collaboration has performed a search for dark matter particles with masses below the GeV-scale with a 33.4-g germanium cryogenic detector operated in a surface lab. The energy deposits were measured using a neutron-transmutation-doped Ge thermal sensor with a 17.7~eV (RMS) baseline heat energy resolution leading to a 60~eV analysis energy threshold. Despite a moderate lead shielding and the high-background environment, the first sub-GeV spin-independent dark matter limit based on a germanium target has been achieved. The experiment provides the most stringent, nuclear recoil based, above-ground limit on spin-independent interactions above 600~MeV/c$^{2}$. The experiment also provides the most stringent limits on spin-dependent interactions with protons and neutrons below 1.3~GeV/c$^{2}$. Furthermore, the dark matter search results were studied in the context of Strongly Interacting Massive Particles, taking into account Earth-shielding effects, for which new regions of the available parameter space have been excluded. Finally, the dark matter search has also been extended to interactions via the Migdal effect, resulting for the first time in the exclusion of particles with masses between 45 and 150~MeV/c$^{2}$ with spin-independent cross sections ranging from $10^{-29}$ to $10^{-26}$~cm$^2$.

astro-ph.GA↗

arXiv2018

Double-beta decay of ${}^{130}$Te to the first $0^+$ excited state of ${}^{130}$Xe with CUORE-0

We report on a search for double beta decay of $^{130}$Te to the first $0^{+}$ excited state of $^{130}$Xe using a 9.8 kg$\cdot$yr exposure of $^{130}$Te collected with the CUORE-0 experiment. In this work we exploit different topologies of coincident events to search for both the neutrinoless and two-neutrino double-decay modes. We find no evidence for either mode and place lower bounds on the half-lives: $τ^{0ν}_{0^+}>7.9\cdot 10^{23}$ yr and $τ^{2ν}_{0^+}>2.4\cdot 10^{23}$ yr. Combining our results with those obtained by the CUORICINO experiment, we achieve the most stringent constraints available for these processes: $τ^{0ν}_{0^+}>1.4\cdot 10^{24}$ yr and $τ^{2ν}_{0^+}>2.5\cdot 10^{23}$ yr.

nucl-ex↗

arXiv2018

Searches for electron interactions induced by new physics in the EDELWEISS-III germanium bolometers

We make use of the EDELWEISS-III array of germanium bolometers to search for electron interactions at the keV scale induced by phenomena beyond the Standard Model. A 90% C.L. lower limit is set on the electron lifetime decaying to invisibles, $τ> 1.2\times 10^{24}$ years. We investigate the emission of axions or axionlike particles (ALPs) by the Sun, constraining the coupling parameters $g_{ae}<1.1\times 10^{-11}$ and $g_{ae}\times g_{aN}^{\rm eff} < 3.5\times 10^{-17}$ at 90% C.L. in the massless limit. We also directly search for the absorption of bosonic dark matter particles that would constitute our local galactic halo. Limits are placed on the couplings of ALPs or hidden photon dark matter in the mass range $0.8 - 500$ keV/c$^2$. Prospects for searching for dark matter particles with masses down to 150 eV/c$^2$ using improved detectors are presented.

hep-ex↗

arXiv2018

Search of the neutrino-less double beta decay of $^{82}$Se into the excited states of $^{82}$Kr with CUPID-0

The CUPID0 experiment searches for double beta decay using cryogenic calorimeters with double (heat and light) read-out. The detector, consisting of 24 ZnSe crystals 95$\%$ enriched in $^{82}$Se and 2 natural ZnSe crystals, started data-taking in 2017 at Laboratori Nazionali del Gran Sasso. We present the search for the neutrino-less double beta decay of $^{82}$Se into the 0$_1^+$, 2$_1^+$ and 2$_2^+$ excited states of $^{82}$Kr with an exposure of 5.74 kg$\cdot$yr (2.24$\times$10$^{25}$ emitters$\cdot$yr). We found no evidence of the decays and set the most stringent limits on the widths of these processes: $Γ$($^{82}$Se $\rightarrow ^{82}$Kr$_{0_1^+}$)$<$8.55$\times$10$^{-24}$ yr$^{-1}$, $Γ$($^{82}$Se $\rightarrow ^{82}$Kr$_{2_1^+}$)$<6.25 \times10^{-24}$ yr$^{-1}$, $Γ$($^{82}$Se $\rightarrow ^{82}$Kr$_{2_2^+}$)$<$8.25$\times$10$^{-24}$ yr$^{-1}$ (90$\%$ credible interval

nucl-ex↗

arXiv2018

Update on the recent progress of the CUORE experiment

CUORE is a 741 kg array of 988 TeO$_2$ bolometeric crystals designed to search for the neutrinoless double beta decay of $^{130}$Te and other rare processes. CUORE has been taking data since summer 2017, and as of summer 2018 collected a total of 86.3 kg$\cdot$yr of TeO$_2$ exposure. Based on this exposure, we were able to set a limit on the $0νββ$ half-life of $^{130}$Te of $T^{0ν}_{1/2}>1.5\times10^{25}$ yr at 90% C.L. At this conference, we showed the decomposition of the CUORE background and were able to extract a $^{130}$Te $2νββ$ half-life of $T_{1/2}^{2ν}=[7.9\pm0.1 \mathrm{(stat.)}\pm0.2 \mathrm{(syst.)}]\times10^{20}$ yr. This is the most precise measurement of this half-life and is consistent with previous measurements.

nucl-ex↗

arXiv2018

Analysis of cryogenic calorimeters with light and heat read-out for double beta decay searches

The suppression of spurious events in the region of interest for neutrinoless double beta decay will play a major role in next generation experiments. The background of detectors based on the technology of cryogenic calorimeters is expected to be dominated by α particles, that could be disentangled from double beta decay signals by exploiting the difference in the emission of the scintillation light. CUPID-0, an array of enriched Zn$^{82}$Se scintillating calorimeters, is the first large mass demonstrator of this technology. The detector started data-taking in 2017 at the Laboratori Nazionali del Gran Sasso with the aim of proving that dual read-out of light and heat allows for an efficient suppression of the α background. In this paper we describe the software tools we developed for the analysis of scintillating calorimeters and we demonstrate that this technology allows to reach an unprecedented background for cryogenic calorimeters.

physics.ins-det↗

arXiv2018

First Result on the Neutrinoless Double Beta Decay of $^{82}$Se with CUPID-0

We report the result of the search for neutrinoless double beta decay of $^{82}$Se obtained with CUPID-0, the first large array of scintillating Zn$^{82}$Se cryogenic calorimeters implementing particle identification. We observe no signal in a 1.83 kg yr $^{82}$Se exposure and we set the most stringent lower limit on the \onu $^{82}$Se half-life T$^{0ν}_{1/2}>$ 2.4$\times \mathrm{10}^{24}$ yr (90\% credible interval), which corresponds to an effective Majorana neutrino mass m$_{ββ} <$ (376-770) meV depending on the nuclear matrix element calculations. The heat-light readout provides a powerful tool for the rejection of \al\ particles and allows to suppress the background in the region of interest down to (3.6$^{+1.9}_{-1.4}$)$\times$10$^{-3}$\ckky, an unprecedented level for this technique.

nucl-ex↗

arXiv2018

Complete event-by-event $α$/$γ(β)$ separation in a full-size TeO$_2$ CUORE bolometer by Neganov-Luke-magnified light detection

In the present work, we describe the results obtained with a large ($\approx 133$ cm$^3$) TeO$_2$ bolometer, with a view to a search for neutrinoless double-beta decay ($0νββ$) of $^{130}$Te. We demonstrate an efficient $α$ particle discrimination (99.9\%) with a high acceptance of the $0νββ$ signal (about 96\%), expected at $\approx 2.5$ MeV. This unprecedented result was possible thanks to the superior performance (10 eV rms baseline noise) of a Neganov-Luke-assisted germanium bolometer used to detect a tiny (70 eV) light signal from the TeO$_2$ detector, dominated by $γ$($β$)-induced Cherenkov radiation but exhibiting also a clear scintillation component. The obtained results represent a major breakthrough towards the TeO$_2$-based version of CUORE Upgrade with Particle IDentification (CUPID), a ton-scale cryogenic $0νββ$ experiment proposed as a follow-up to the CUORE project with particle identification. The CUORE experiment began recently a search for neutrinoless double-beta decay of $^{130}$Te with an array of 988 125-cm$^3$ TeO$_2$ bolometers. The lack of $α$ discrimination in CUORE makes $α$ decays at the detector surface the dominant background component, at the level of $\approx 0.01$ counts/(keV kg y) in the region of interest. We show here, for the first time with a CUORE-size bolometer and using the same technology as CUORE for the readout of both heat and light signals, that surface $α$ background can be fully rejected.

physics.ins-det↗

arXiv2018

First scintillating bolometer tests of a CLYMENE R&D on Li$_2$MoO$_4$ scintillators towards a large-scale double-beta decay experiment

A new R&D on lithium molybdate scintillators has begun within a project CLYMENE (Czochralski growth of Li$_2$MoO$_4$ crYstals for the scintillating boloMeters used in the rare EveNts sEarches). One of the main goals of the CLYMENE is a realization of a Li$_2$MoO$_4$ crystal growth line to be complementary to the one recently developed by LUMINEU in view of a mass production capacity for CUPID, a next-generation tonne-scale bolometric experiment to search for neutrinoless double-beta decay. In the present paper we report the investigation of performance and radiopurity of 158-g and 13.5-g scintillating bolometers based on a first large-mass (230 g) Li$_2$MoO$_4$ crystal scintillator developed within the CLYMENE project. In particular, a good energy resolution (2--7 keV FWHM in the energy range of 0.2--5 MeV), one of the highest light yield (0.97 keV/MeV) amongst Li$_2$MoO$_4$ scintillating bolometers, an efficient alpha particles discrimination (10$σ$) and potentially low internal radioactive contamination (below 0.2--0.3 mBq/kg of U/Th, but 1.4 mBq/kg of $^{210}$Po) demonstrate prospects of the CLYMENE in the development of high quality and radiopure Li$_2$MoO$_4$ scintillators for CUPID.

physics.ins-det↗