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Pettinacci, V.

Publications and source records attributed to Pettinacci, V..

At least 37 records · Page 2

Search for lepton flavour violating muon decay mediated by a new light particle in the MEG experiment

We present the first direct search for lepton flavour violating muon decay mediated by a new light particle X, μ + → e + X,X → γγ . This search uses a dataset resulting from 7.5 × 10 14 stopped muons collected by the MEG experiment at the Paul Scherrer Institut in the period 2009–2013. No significant excess is found in the mass region 20–45 MeV/c 2 for lifetimes below 40 ps, and we set the most stringent branching ratio upper limits in the mass region of 20–40 MeV/c 2 , down to O(10 –11 ) at 90% confidence level.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Lowering the Energy Threshold of the CUORE Experiment: Benefits in the Surface Alpha Events Reconstruction

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 of 130 Te. Thanks to its very low background and large mass, CUORE is also a powerful tool to study a broad class of phenomena, such as solar axions and WIMP scattering. The ability to conduct such sensitive searches crucially depends on the energy threshold, which has to be kept as low as possible. Here, we show how the trigger algorithm affects the sensitivity to low-energy phenomena and the interpretation of the energy spectrum. In particular, we focus on the impact that the trigger algorithm has on the identification of the coincidence events among different crystals and, consequently, on the reconstruction of the background.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

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 TeO 2 crystals (742 kg) arranged in a compact cylindrical structure of 19 towers. Here, 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 130 Te 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.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Improved Limit on Neutrinoless Double-Beta Decay in Te 130 with CUORE

We report new results from the search for neutrinoless double-beta decay in $^{130}$Te with the CUORE detector. This search benefits from a four-fold increase in exposure, lower trigger thresholds and analysis improvements relative to our previous results. We observe a background of $(1.38\pm0.07)\cdot10^{-2}$ counts$/($keV$\cdot$kg$\cdot$yr$)$ in the $0\nu\beta\beta$ decay region of interest and, with a total exposure of 372.5 kg$\cdot$yr, we attain a median exclusion sensitivity of $1.7\cdot10^{25}$ yr. We find no evidence for $0\nu\beta\beta$ decay and set a $90\%$ CI Bayesian lower limit of $3.2\cdot10^{25}$ yr on the $^{130}$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.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

The CUORE Detector and Results

The cryogenic underground observatory for rare events (CUORE) is a cryogenic experiment searching for neutrinoless double beta decay (0νββ) of 130 Te. The detector consists of an array of 988TeO 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 0νββ and 2νββ decay of 130 Te obtained from the analysis of the physics data acquired in 2017.

0vββ↗

Double-beta decay of $^{130}\hbox {Te}$ to the first $0^+$ excited state of $^{130}\hbox {Xe}$ 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 9.8kg·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 beta decay modes. We find no evidence for either mode and place lower bounds on the half-lives: $T_{0_1^+}^{0ν}$ > 7.9·10 23 yr and $T_{0_1^+}^{2ν}$ > 2.4·10 23 yr (90%CL). Combining our results with those obtained by the CUORICINO experiment, we achieve the most stringent constraints available for these processes: $T_{0_1^+}^{0ν}$ > 1.4·10 24 yr and $T_{0_1^+}^{2ν}$ > 2.5·10 23 yr (90%CL).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Monte Carlo simulation of the SABRE PoP background

SABRE (Sodium-iodide with Active Background REjection) is a direct dark matter search experiment based on an array of radio-pure NaI(Tl) crystals surrounded by a liquid scintillator veto. Twin SABRE experiments in the Northern and Southern Hemispheres will differentiate a dark matter signal from seasonal and local effects. The experiment is currently in a Proof-of-Principle (PoP) phase, whose goal is to demonstrate that the background rate is low enough to carry out an independent search for a dark matter signal, with sufficient sensitivity to confirm or refute the DAMA result during the following full-scale experimental phase. As such, the impact of background radiation from the detector materials and the experimental site needs to be carefully investigated, including both intrinsic and cosmogenically activated radioactivity. Based on the best knowledge of the most relevant sources of background, we have performed a detailed Monte Carlo study evaluating the expected background in the dark matter search spectral region. The simulation model described in this paper guides the design of the full-scale experiment and will be fundamental for the interpretation of the measured background and hence for the extraction of a possible dark matter signal.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

CUPID-0: the first array of enriched scintillating bolometers for 0$\nu \beta \beta$ decay investigations

The CUPID-0 detector hosted at the Laboratori Nazionali del Gran Sasso, Italy, is the first large array of enriched scintillating cryogenic detectors for the investigation of 82 Se neutrinoless double-beta decay (0$\nu \beta \beta$). CUPID0 aims at measuring a background index in the region of interest (RoI) for 0$\nu \beta \beta$ at the level of 10 -3 counts/(keV kg years), the lowest value ever measured using cryogenic detectors. CUPID-0 operates an array of Zn 82 Se scintillating bolometers coupled with bolometric light detectors, with a state of the art technology for background suppression and thorough protocols and procedures for the detector preparation and construction. In this paper, the different phases of the detector design and construction will be presented, from the material selection (for the absorber production) to the new and innovative detector structure. The successful construction of the detector lead to promising preliminary detector performance which is discussed here.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

The Cryogenic Underground Observatory for Rare Events: Status and Prospects

The Cryogenic Underground Observatory for Rare Events (CUORE) is a large-scale double beta decay experiment utilizing cryogenic bolometers that is currently being commissioned at the Gran Sasso National Laboratory (LNGS) in Italy. Its primary focus is to search for the neutrino-less double beta decay of 130Te with a projected sensitivity to Majorana neutrino masses near the inverted mass hierarchy region. The detector is composed of 988 5x5x5-cm 3 TeO 2 crystals of natural isotopic composition arranged in 19 towers of 52 crystals each, all housed in a common dilution refrigerator. A single CUORE-like tower, CUORE-0, was assembled and operated as a stand-alone detector for a period of approximately two years. In this report, the results from CUORE-0 and the current status and physics potential of CUORE are presented.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

the Cryogenic Underground Observatory for Rare Events: Status and Prospects

The Cryogenic Underground Observatory for Rare Events (CUORE) is a large-scale double beta decay experiment utilizing cryogenic bolometers that is currently being commissioned at the Gran Sasso National Laboratory (LNGS) in Italy. Its primary focus is to search for the neutrinoless double beta decay of 130Te with a projected sensitivity to Majorana neutrino masses near the inverted mass hierarchy region. The detector is composed of 988 5x5x5-cm 3 TeO 2 crystals of natural isotopic composition arranged in 19 towers of 52 crystals each, all housed in a common dilution refrigerator. A single CUORE-like tower, CUORE-0, was assembled and operated as a stand-alone detector for a period of approximately two years. In this report, the results from CUORE-0 and the current status and physics potential of CUORE are presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

The CUORE cryostat and its bolometric detector

CUORE is a cryogenic detector that will be operated at LNGS to search for neutrinoless double beta decay (0νββ) of 130 Te. The detector installation was completed in summer 2016. Before the installation, several cold runs were done to test the cryogenic system performance. In the last cold run the base temperature of 6.3 mK was reached in stable condition. CUORE-0, a CUORE prototype, has proven the feasibility of CUORE, demonstrating that the target background of 0.01 counts/keV/kg/y and the energy resolution of 5 keV are within reach.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

First array of enriched Zn$^{82}$Se bolometers to search for double beta decay

The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in 82 Se, the Zn 82 Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn 82 Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-o.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Results from the CUORE-0 experiment

The CUORE-0 experiment searched for neutrinoless double beta decay in 130 Te using an array of 52 tellurium dioxide crystals, operated as bolometers at a temperature of 10 mK. It took data in the Gran Sasso National Laboratory (Italy) since March 2013 to March 2015. We present the results of a search for neutrinoless double beta decay in 9.8 kg-years 130 Te exposure that allowed us to set the most stringent limit to date on this half-life. The performance of the detector in terms of background and energy resolution is also reported.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Status of the CUORE and results from the CUORE-0 neutrinoless double beta decay experiments

CUORE is a 741 kg array of TeO 2 bolometers for the search of neutrinoless double beta decay of 130 Te. The detector is being constructed at the Laboratori Nazionali del Gran Sasso, Italy, where it will start taking data in 2015. If the target background of 0.01 counts/(keV·kg·y) will be reached, in five years of data taking CUORE will have a 1σ half life sensitivity of 10 26 y. CUORE-0 is a smaller experiment constructed to test and demonstrate the performances expected for CUORE. The detector is a single tower of 52 CUORE-like bolometers that started taking data in spring 2013. The status and perspectives of CUORE will be discussed, and the first CUORE-0 data will be presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Analysis techniques for the evaluation of the neutrinoless double- β decay lifetime in Te 130 with the CUORE-0 detector

We describe in detail the methods used to obtain the lower bound on the lifetime of neutrinoless double-beta ( 0 ν β β ) decay in 130 Te and the associated limit on the effective Majorana mass of the neutrino using the CUORE-0 detector. CUORE-0 is a bolometric detector array located at the Laboratori Nazionali del Gran Sasso that was designed to validate the background reduction techniques developed for CUORE, a next-generation experiment scheduled to come online in 2016. CUORE-0 is also a competitive 0 ν β β decay search in its own right and functions as a platform to further develop the analysis tools and procedures to be used in CUORE. These include data collection, event selection and processing, as well as an evaluation of signal efficiency. In particular, we describe the amplitude evaluation, thermal gain stabilization, energy calibration methods, and the analysis event selection used to create our final 0 ν β β search spectrum. We define our high level analysis procedures, with emphasis on the new insights gained and challenges encountered. We outline in detail our fitting methods near the hypothesized 0 ν β β decay peak and catalog the main sources of systematic uncertainty. Finally, we derive the 0 ν β β decay half-life limits previously reported for CUORE-0, T 0 ν 1 / 2 > 2.7 × 10 24 yr , and in combination with the Cuoricino limit, T 0 ν 1 / 2 > 4.0 × 10 24 yr .

22 GENERAL STUDIES OF NUCLEAR REACTORS↗