Cryogenic Underground Observatory For Rare Events Research Articles

Recent progresses on BSM and dark matter searches with CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric 0\nu\beta\beta0νββ experiment to reach the one-tonne mass scale. The detector, located underground at the Laboratori Nazionali del Gran Sasso in Italy, consists of 988 TeO_22 crystals arranged in a compact cylindrical structure of 19 towers, operating at a base temperature of about 10 mK. After beginning its first physics data run in 2017, CUORE has since collected the largest amount of data ever acquired with a solid state detector and provided the most sensitive measurement of 0\nu\beta\beta0νββ decay in ^{130}130Te ever conducted. The large exposure, sharp energy resolution, segmented structure and radio-pure environment make CUORE an ideal instrument for a wide array of searches for rare events and symmetry violations. New searches for low mass dark matter, solar axions, CPT and Lorenz violations, and refined measurements of the 2\nu\beta\beta2νββ spectrum in CUORE have the potential to provide new insight and constraints on extensions to the standard model complementary to other particle physics searches. In this contribution, the recent progress on BSM and dark matter searches in CUORE are discussed.

New Direct Limit on Neutrinoless Double Beta Decay Half-Life of Te128 with CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) at Laboratori Nazionali del Gran Sasso of INFN in Italy is an experiment searching for neutrinoless double beta (0νββ) decay. Its main goal is to investigate this decay in ^{130}Te, but its ton-scale mass and low background make CUORE sensitive to other rare processes as well. In this Letter, we present our first results on the search for 0νββ decay of ^{128}Te, the Te isotope with the second highest natural isotopic abundance. We find no evidence for this decay, and using a Bayesian analysis we set a lower limit on the ^{128}Te 0νββ decay half-life of T_{1/2}>3.6×10^{24} yr (90% CI). This represents the most stringent limit on the half-life of this isotope, improving by over a factor of 30 the previous direct search results, and exceeding those from geochemical experiments for the first time.

An energy-dependent electro-thermal response model of CUORE cryogenic calorimeter

The Cryogenic Underground Observatory for Rare Events (CUORE) is the most sensitive experiment searching for neutrinoless double-beta decay (0νββ) in 130Te. CUORE uses a cryogenic array of 988 TeO2 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.

Latest Results from the CUORE Experiment

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first cryogenic experiment searching for 0nu beta beta decay that has been able to reach the one-tonne mass scale. The detector, located at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy, consists of an array of 988 {mathrm{TeO}}_{2} crystals arranged in a compact cylindrical structure of 19 towers. CUORE began its first physics data run in 2017 at a base temperature of about 10 mK and in April 2021 released its 3{mathrm{rd}} result of the search for 0nu beta beta , corresponding to a tonne-year of mathrm{TeO}_{2} exposure. This is the largest amount of data ever acquired with a solid state detector and the most sensitive measurement of 0nu beta beta decay in {}^{130}mathrm{Te} ever conducted . We present the current status of CUORE search for 0nu beta beta with the updated statistics of one tonne-yr. We finally give an update of the CUORE background model and the measurement of the {}^{130}mathrm{Te}2nu beta beta decay half-life and decay to excited states of {}^{130}mathrm{Xe}, studies performed using an exposure of 300.7 kg yr.

Search for neutrinoless β+ EC decay of Te120 with CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) is a large-scale cryogenic experiment searching for neutrinoless double-beta decay (0νββ) in Te130. The CUORE detector is made of natural tellurium, providing the possibility of rare event searches on isotopes other than Te130. In this work we describe a search for neutrinoless positron-emitting electron capture (β+EC) decay in Te120 with a total TeO2 exposure of 355.7 kg yr, corresponding to 0.2405 kg yr of Te120. Albeit 0νββ with two final-state electrons represents the most promising channel, the emission of a positron and two 511-keV γ's make 0νβ+EC decay signature extremely clear. To fully exploit the potential offered by the detector modularity we include events with different topology and perform a simultaneous fit of five selected signal signatures. Using blinded data we extract a median exclusion sensitivity of 3.4×1022 yr at 90% credibility interval (C.I.). After unblinding we find no evidence of 0νβ+EC signal and set a 90% C.I. Bayesian lower limit of 2.9×1022 yr on Te120 half-life. This result improves by an order of magnitude the existing limit from the combined analysis of CUORE-0 and Cuoricino.Received 25 March 2022Accepted 27 May 2022DOI:https://doi.org/10.1103/PhysRevC.105.065504©2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasDouble beta decayNeutrinoless double beta decayRare decaysPhysical SystemsMajorana neutrinosProperties90 ≤ A ≤ 149Baryon & lepton number symmetriesNuclear PhysicsParticles & Fields

New results from the CUORE experiment

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrino-less double-beta (0[Formula: see text]) decay that has been able to reach the one-ton scale. The detector, located at the Laboratori Nazionali del Gran Sasso in Italy, consists of an array of 988 TeO2 crystals arranged in a compact cylindrical structure of 19 towers. Following the completion of the detector construction in August 2016, CUORE began its first physics data run in 2017 at a base temperature of about 10 mK. Following multiple optimization campaigns in 2018, CUORE is currently in stable operating mode. In 2019, CUORE released its second result of the search for 0[Formula: see text] corresponding to a TeO2 exposure of 372.5 kg[Formula: see text]⋅[Formula: see text]yr and a median exclusion sensitivity to a 130Te 0[Formula: see text] decay half-life of [Formula: see text] yr. We find no evidence for 0[Formula: see text] decay and set a 90% C.I. Bayesian lower limit of [Formula: see text] yr on the 130Te 0[Formula: see text] decay half-life. We present the current status of CUORE’s search for 0[Formula: see text]. We give an update of the CUORE background model and the measurement of the 130Te two neutrino double-beta (2[Formula: see text]) decay half-life. Eventually, we show the preliminary results on half-life limits from the analysis of 130Te 0[Formula: see text] and 2[Formula: see text] decay to the first 0[Formula: see text] excited state of [Formula: see text]Xe.

Synthetic data for the study of the CUORE detector response function

CUORE (Cryogenic Underground Observatory for Rare Events) is a ton-scale experiment located at LNGS (Laboratori Nazionali del Gran Sasso) in Italy whose goal is to search for neutrino-less double beta decay (0υββ) in 130Te.CUORE exploits an array of 988 TeO2 crystals operated as Low-Temperature Detectors (LTDs) at 10 mK. These detectors show an excellent energy resolution, making the experiment one of the most competitive 0υββ searches in the world. In this scenario, the proposed research deals with the generation of synthetic (mock) data for the study of the CUORE detector response function. The production of synthetic data is a new tool we designed to consider all the missing information from a Montecarlo simulation: the detector non-idealities, as well as noise and pulse shape. The mock data are processed with the CUORE official analysis software, allowing us the evaluation of its impact on the final results.

The search for neutrinoless positron emitting electron capture (0υECβ +) of 120Te with CUORE

CUORE (Cryogenic Underground Observatory for Rare Events) is a tonne-scale experiment located at the LNGS with the main scientific goal of searching for neutrinoless double beta decay in 130Te. The detector consists of TeO2 crystals operated as cryogenic calorimeters. The use of natural tellurium allows us to search for other isotopes rare decays. The neutrinoless positron emitting electron capture (0υECβ +) of 120Te (natural abundance 0.09(1)%) has a clear signature from the 511-keV annihilation γ rays. We present an analysis of this process based on a new algorithm to perform the simultaneous spectral fit over five selected decay scenarios. Each scenario is characterized by a set of crystals simultaneously interested by a detectable energy release. We describe the background structure modeling and tests of linearity we performed on the fit algorithm. We finally present the limit setting sensitivity and the next steps of this study, including systematics accounting.

Development of Cryogenic Detectors for Neutrinoless Double Beta Decay Searches with CUORE and CUPID

Searching for neutrinoless double beta decay is a top priority in particle and astroparticle physics, being the most sensitive test of lepton number violation and the only suitable process to probe the Majorana nature of neutrinos. In order to increase the experimental sensitivity for this particular search, ton-scale detectors operated at nearly zero-background conditions with a low keV energy resolution at the expected signal peak are required. In this scenario, cryogenic detectors have been proven effective in addressing many of these issues simultaneously. After long technical developments, the Cryogenic Underground Observatory for Rare Events (CUORE) experiment established the possibility to operate large-scale detectors based on this technology. Parallel studies pointed out that scintillating cryogenic detectors represent a suitable upgrade for the CUORE design, directed towards higher sensitivities. In this work, we review the recent development of cryogenic detectors, starting from the state-of-the-art and outlying the path toward next-generation experiments.

Status and results from the CUORE experiment

The Cryogenic Underground Observatory for Rare Events (CUORE) is a tonne-scale cryogenic experiment located at the Laboratori Nazionali del Gran Sasso that exploits bolometric technique to search for neutrinoless double beta decay [Formula: see text] of [Formula: see text]Te. The detector consists of a segmented array of 988 natural [Formula: see text] cubic crystals arranged in a cylindrical compact structure of 19 towers. The detector construction was completed in August 2016 and data taking started in Spring 2017. In this work, we present a brief description of the bolometric technique for rare events search and the CUORE detector, then we concentrate on the data analysis results. In this respect, we focus on the procedure for data processing and on the first [Formula: see text] results we obtained from a total [Formula: see text] exposure of [Formula: see text]. Next, we illustrate the main background sources and the CUORE background model, from which we obtain the most precise measurement of [Formula: see text]Te [Formula: see text] half-life to date. Finally, we discuss the improvements achieved with 2018 and 2019 detector optimization campaigns and the current perspectives of our experiment.

The CUORE Detector and Results

The cryogenic underground observatory for rare events (CUORE) is a cryogenic experiment searching for neutrinoless double beta decay ($$0\nu \beta \beta$$) of $${^{130}\hbox {Te}}$$. The detector consists of an array of $$988\,{\hbox {TeO}_{2}}$$ crystals arranged in a compact cylindrical structure of 19 towers. We report the CUORE initial operations and optimization campaigns. We then present the CUORE results on $$0\nu \beta \beta$$ and $$2\nu \beta \beta$$ decay of $${^{130}\hbox {Te}}$$ obtained from the analysis of the physics data acquired in 2017.

First results from the CUORE experiment

CUORE (Cryogenic Underground Observatory for Rare Events) is a ton-scale experiment aiming to the search of neutrino-less double beta decay in 130Te with a projected sensitivity on the Majorana effective mass close to the inverted hierarchy region. The CUORE detector consists of a segmented array of 988 TeO2 bolometers, organized in 19 towers and operated at a temperature of about 10 mK thanks to a custom cryogenic system which, besides the uncommon scale, observes several constraints from the radio-purity of the materials to the mechanical decoupling of the cooling systems. The successful commissioning of the CUORE cryogenic system has been completed early in 2016 and represents an outstanding achievement by itself. The installation of the detector proceeded along 2016 followed by the cooldown to base temperature at the beginning of 2017. The CUORE detector is now operational and has been taking science data since Spring 2017. With the first ~3 weeks of collected data, we present here the most stringent constraint on the 130Te half-live for the neutrino-less double beta decay.

CUORE: The first bolometric experiment at the ton scale for the search for neutrino-less double beta decay

The Cryogenic Underground Observatory for Rare Events (CUORE) is the most massive bolometric experiment searching for neutrino-less double beta (0νββ) decay. The detector consists of an array of 988 TeO2 crystals (742 kg) arranged in a compact cylindrical structure of 19 towers. This paper will describe the CUORE experiment, including the cryostat, and present the detector performance during the first year of running. Additional detail will describe the effort made in improving the energy resolution in the 130Te 0νββ decay region of interest (ROI) and the suppression of backgrounds. A description of work to lower the energy threshold in order to give CUORE the sensitivity to search for other rare events, such as dark matter, will also be provided.

Results from the Cuore Experiment †

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO 2 crystals arranged in a cylindrical compact structure of 19 towers, each of them made of 52 crystals. The construction of the experiment was completed in August 2016 and the data taking started in spring 2017 after a period of commissioning and tests. In this work we present the neutrinoless double beta decay results of CUORE from examining a total TeO 2 exposure of 86.3 kg yr , characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts / ( keV kg yr ) . In this physics run, CUORE placed a lower limit on the decay half-life of neutrinoless double beta decay of 130 Te > 1.3 · 10 25 yr (90% C.L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130 Te 2 ν β β decay with a resulting half-life of T 1 / 2 2 ν = [ 7.9 ± 0.1 ( stat . ) ± 0.2 ( syst . ) ] × 10 20 yr which is the most precise measurement of the half-life and compatible with previous results.

Results from the CUORE experiment

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta (0νββ) decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. The construction of the experiment and, in particular, the installation of all towers in the cryostat was completed in 2016 and data taking started in 2017. In this conference we present the 0νββ decay results of CUORE from examining a total TeO2 exposure of 86.3 kg yr, characterized by an effective energy resolution of 7.7 keV FWHM and a background in the region of interest of 0.014 counts/(keV kg yr). Based on these data, CUORE places a lower limit on the 0νββ decay half-life of (90% C.L.). We then discuss the latest updates in the analysis of background and in the evaluation of the half-life of 2νββ decay of 130Te.

CUORE: The first bolometric experiment at the ton scale for rare decay searches

Author(s): Adams, DQ; Alduino, C; Alfonso, K; Avignone, FT; Azzolini, O; Bari, G; Bellini, F; Benato, G; Bersani, A; Biassoni, M; Branca, A; Brofferio, C; Bucci, C; Caminata, A; Campani, A; Canonica, L; Cao, XG; Capelli, S; Cappelli, L; Cardani, L; Carniti, P; Casali, N; Cassina, L; Chiesa, D; Chott, N; Clemenza, M; Copello, S; Cosmelli, C; Cremonesi, O; Creswick, RJ; Cushman, JS; D'Addabbo, A; D'Aguanno, D; Dafinei, I; Davis, CJ; Dell'Oro, S; Deninno, MM; Domizio, SD; Vacri, MLD; Dompe, V; Drobizhev, A; Fang, DQ; Faverzani, M; Ferri, E; Ferroni, F; Fiorini, E; Franceschi, MA; Freedman, SJ; Fujikawa, BK; Giachero, A; Gironi, L; Giuliani, A; Gladstone, L; Gorla, P; Gotti, C; Gutierrez, TD; Han, K; Heeger, KM; Hennings-Yeomans, R; Huang, RG; Huang, HZ; Johnston, J; Keppel, G; Kolomensky, YG; Leder, A; Ligi, C; Ma, YG; Marini, L; Martinez, M; Maruyama, RH; Mei, Y; Moggi, N; Morganti, S; Nagorny, SS; Napolitano, T; Nastasi, M; Nones, C; Norman, EB; Novati, V; Nucciotti, A; Nutini, I; O'Donnell, T; Ouellet, JL; Pagliarone, CE; Pallavicini, M | Abstract: The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. The construction of the experiment and, in particular, the installation of all towers in the cryostat was completed in August 2016 and data taking started in spring 2017. In this contribution the achievement of the commissioning phase and the performance of the detector and the cryostat during the first physics run will be presented.

The CUORE Cryostat

The Cryogenic Underground Observatory for Rare Events (CUORE) is a bolometric experiment for neutrinoless double-beta decay in $^{130}$Te search, currently taking data at the underground facility of Laboratori Nazionali del Gran Sasso (LNGS). The CUORE cryostat successfully cooled down a mass of about 1 ton at $\sim$7\,mK, delivering an uniform and constant base temperature. This result marks a fundamental milestone in low temperature detectors techniques, opening the path for future ton-scale bolometric experiments searching for rare events. In this paper we present the CUORE cryogenic infrastructure, briefly describing its critical subsystems.

The CUORE and CUORE-0 experiments at LNGS

The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for neutrinoless double beta decay that has been able to reach the 1-ton scale. The detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. The construction of the experiment and, in particular, the installation of all towers in the cryostat was completed in August 2016 and commissioning started in fall 2016. The experiment has completed the pre-operation phase and is currently in data taking. We present here the achievements of CUORE during the commissioning phase and the limit on the 130Te half-life for the neutrinoless double beta decay that has been released after the first 3 weeks of collected data. Physics results from CUORE-0 will also be updated.

An active noise cancellation technique for the CUORE Pulse Tube cryocoolers

The Cryogenic Underground Observatory for Rare Events (CUORE) experiment at Gran Sasso National Laboratory of INFN searches for neutrinoless double beta decay using TeO2 crystals as cryogenic bolometers. The sensitivity of the measurement heavily depends on the energy resolution of the detector, therefore the success of the experiment stands on the capability to provide an extremely low noise environment. One of the most relevant sources of noise are the mechanical vibrations induced by the five Pulse Tube cryocoolers used on the cryogenic system which houses the detectors. To address this problem, we developed a system to control the relative phases of the pulse tube pressure oscillations, in order to achieve coherent superposition of the mechanical vibrations transmitted to the detectors. In the following, we describe this method and report on the results in applying it to the CUORE system.

The CUORE experiment at LNGS

Since the discovery of neutrino, many of its properties have been studied. The flavor oscillations recently revealed that, contrary to the Standard Model assumptions, neutrinos have a finite mass. Other neutrino characteristics are still to be investigated, such as its Dirac or Majorana nature: experiments are currently searching for a rare phenomenon, the neutrinoless double beta decay (0νββ), whose observation would solve this issue. The Cryogenic Underground Observatory for Rare Events (CUORE) at Gran Sasso National Laboratories focuses on the search of 130Te 0νββ and it is the first ton-scale bolometric experiment ever realized for this purpose. The detector is hosted inside a custom cryostat and consists of 988 TeO2 crystals, operated at a temperature of ∼ 10 mK. The CUORE goals in 5 years of data taking are an energy resolution of 5 keV FWHM and a background level of 0.01 counts/keV/kg/y in the 130Te 0νββ region of interest. This corresponds to a sensitivity on the 130Te 0νββ half life of T1/2 = 9 · 1025 y (90% C.L.) and an upper limit to the effective Majorana mass of 50 − 130 meV. The CUORE commissioning has been recently completed; the experiment has just concluded the pre-operation phase and data taking is currently ongoing.