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 TeO2 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 TeO2 exposure of 86.3kg 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 130Te \u3e 1.3.1025 yr (90% C. L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130Te 2 &nuββ decay with a resulting half- life of T 2v 1/2 = [7.9 ±0.1 (stat.) ±0.2 (syst.)] x 1020 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 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, 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 TeO2 exposure of 86.3kg 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 130Te > 1.3.1025 yr (90% C. L.). Moreover, an analysis of the background of the experiment is presented as well as the measurement of the 130Te 2vo3p decay with a resulting half- life of T2 2. [7.9 :- 0.1 (stat.) :- 0.2 (syst.)] x 10(20) yr which is the most precise measurement of the half- life and compatible with previous results

The search for neutrinoless double beta decay of 130Te and 120Te with the CUORE experiment

The discovery of neutrino masses through the observation of oscillations has boosted the importance of neutrinoless double beta decay (0\u3bd\u3b2\u3b2). This rare process is a direct probe of Beyond the Standard Model Physics, since it violates the lepton number by two units. Furthermore, 0\u3bd\u3b2\u3b2 allows us to investigate the Dirac/Majorana nature of the neutrino and to get information on the neutrino absolute mass scale and ordering. This thesis work is developed in the framework of the CUORE experiment. CUORE (Cryogenic Underground Observatory for Rare Events) is a tonne-scale bolometric experiment whose main goal is the search for the 0\u3bd\u3b2\u3b2 of 130Te. The experiment is currently taking data at the Laboratori Nazionali del Gran Sasso (Italy). In the first part of the thesis, the Physics of interest for CUORE and the experimental aspects are introduced. A general overview of the current knowledge in neutrino physics is presented. 0\u3bd\u3b2\u3b2 process is introduced within the particle physics scenario in which the Majorana mass of ordinary neutrinos dominate the decay rate. Then, the experimental challenge the observation of double beta decay represents is discussed. After a general overview of the bolometric technique for rare events search, a general description of the CUORE experiment is outlined. Details on the main components of the CUORE detector are provided, focusing on the stringent requirements in terms of background and noise reduction they must satisfy. Finally, we illustrate the calibration system of the CUORE detector, comparing two alternative approaches employed in terms of compliance with the cryogenic infrastructure and performance. The second part of the thesis focuses on the data processing chain. The most important stages of the low level data analysis include the evaluation of signal amplitude, the energy calibration and the identification of coincident events between the detectors. We present a preliminary analysis of the improvements we obtain in the background reconstruction with the optimum trigger and discuss the performance of the external detector calibration system. Finally, we describe the steps to characterise our detector in terms of efficiency of the selection cuts and energy response function. The core of the thesis focuses on two physical analysis, the search for 0\u3bd\u3b2\u3b2 decay of 130Te with a total TeO2 exposure of 372.5 kg \ub7 yr, and the search for neutrinoless double emitting electron capture (0\u3bdEC\u3b2+) decay of 120Te with 355.7 kg \ub7 yr TeO2 exposure. The data selection and the fit strategy for the search of 0\u3bd\u3b2\u3b2 decay in 130Te are discussed in detail. An interpretation of the final result on the 0\u3bd\u3b2\u3b2 decay rate estimate is given, with an overview of the major sources of uncertainty on the final results. Then, we present the analysis of a specific double beta decay mode of 120Te. We start introducing the motivations behind a growing interest for the (neutrinoless) double beta decay modes different from \u3b2 12\u3b2 12, where electrons are emitted. Then, we describe the physical process analyzed in this dissertation, pointing out the requirements we set to identify candidate signal events. We discuss our data selection, specifying differences with respect to the 0\u3bd\u3b2\u3b2 decay analysis of 130Te and we illustrate the statistical approach. Given the complexity of this analysis a preliminary result on the 120Te rate for 0\u3bdEC\u3b2+ is presented, and the future developments of this study are also introduced

Status and Perspectives on Rare Decay Searches in Tellurium Isotopes

Neutrinoless double beta decay (0νββ) is a posited lepton number violating decay whose search is an increasingly active field in modern astroparticle physics. A discovery would imply neutrinos are Majorana particles and inform neutrino physics, cosmology and beyond-standard- model theories. Among the few nuclei where double beta decay (ββ) is allowed, tellurium isotopes stand for their high natural abundance and are currently employed in multiple experiments. The search for 0νββ will provide large exposure data sets in the coming years, paving the way for unprecedented sensitivities. We review the latest rare decay searches in tellurium isotopes and compare past results with theories and prospects from running experiments

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

Abstract 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 $$^{130}{\hbox {Te}}$$ 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. In this contribution, 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

Performance of a modular ton-scale pixel-readout liquid argon time projection chamber

The Module-0 Demonstrator is a single-phase 600 kg liquid argon time projection chamber operated as a prototype for the DUNE liquid argon near detector. Based on the ArgonCube design concept, Module-0 features a novel 80k-channel pixelated charge readout and advanced high-coverage photon detection system. In this paper, we present an analysis of an eight-day data set consisting of 25 million cosmic ray events collected in the spring of 2021. We use this sample to demonstrate the imaging performance of the charge and light readout systems as well as the signal correlations between the two. We also report argon purity and detector uniformity measurements, and provide comparisons to detector simulations

Performance of a modular ton-scale pixel-readout liquid argon time projection chamber

International audienceThe Module-0 Demonstrator is a single-phase 600 kg liquid argon time projection chamber operated as a prototype for the DUNE liquid argon near detector. Based on the ArgonCube design concept, Module-0 features a novel 80k-channel pixelated charge readout and advanced high-coverage photon detection system. In this paper, we present an analysis of an eight-day data set consisting of 25 million cosmic ray events collected in the spring of 2021. We use this sample to demonstrate the imaging performance of the charge and light readout systems as well as the signal correlations between the two. We also report argon purity and detector uniformity measurements, and provide comparisons to detector simulations

Performance of a modular ton-scale pixel-readout liquid argon time projection chamber

International audienceThe Module-0 Demonstrator is a single-phase 600 kg liquid argon time projection chamber operated as a prototype for the DUNE liquid argon near detector. Based on the ArgonCube design concept, Module-0 features a novel 80k-channel pixelated charge readout and advanced high-coverage photon detection system. In this paper, we present an analysis of an eight-day data set consisting of 25 million cosmic ray events collected in the spring of 2021. We use this sample to demonstrate the imaging performance of the charge and light readout systems as well as the signal correlations between the two. We also report argon purity and detector uniformity measurements, and provide comparisons to detector simulations

Performance of a modular ton-scale pixel-readout liquid argon time projection chamber

International audienceThe Module-0 Demonstrator is a single-phase 600 kg liquid argon time projection chamber operated as a prototype for the DUNE liquid argon near detector. Based on the ArgonCube design concept, Module-0 features a novel 80k-channel pixelated charge readout and advanced high-coverage photon detection system. In this paper, we present an analysis of an eight-day data set consisting of 25 million cosmic ray events collected in the spring of 2021. We use this sample to demonstrate the imaging performance of the charge and light readout systems as well as the signal correlations between the two. We also report argon purity and detector uniformity measurements, and provide comparisons to detector simulations