Results from the CUORE experiment CUORE Matteo Biassoni on behalf of - PowerPoint PPT Presentation

Results from the CUORE experiment CUORE Matteo Biassoni on behalf of the CUORE Collaboration INFN - Sez. Milano Bicocca M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019

Outline CUORE • TeO 2 and thermal detectors for neutrino-less DBD • CUORE setup ‣ Location ‣ Cryogenic system ‣ Calibration system ‣ Shielding • CUORE roadmap • Analysis procedures ‣ Calibration and detector response ‣ Event selection and topology • Physics results ‣ 0 νββ and lepton number violation ‣ background model ‣ 2 νββ • Conclusions and outlook M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 2

Outline CUORE • TeO 2 and thermal detectors for neutrino-less DBD • CUORE setup ‣ Location ‣ Cryogenic system ‣ Calibration system ‣ Shielding • CUORE roadmap • Analysis procedures ‣ Calibration and detector response ‣ Event selection and topology • Physics results ‣ 0 νββ and lepton number violation ‣ background model ‣ 2 νββ • Conclusions and outlook M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 3

TeO 2 and thermal detectors for 0 ν DBD CUORE 130 Te is a good candidate source Second order nuclear process, alternative to beta decay forbidden for 0 ν DBD search: by mass difference for some even-even nuclei • high natural isotopic abundance (~34%) ( A, Z ) → ( A, Z + 2) + 2 e − + 2¯ • NME and phase space on 2nd order SM process, T 1/2 ~10 18~24 years ν e average • Q-value (2528 keV) above ( A, Z ) → ( A, Z + 2) + 2 e − most of the natural radioactivity • SM forbidden, Δ L = 2 • easy to mix in convenient • if observed, then neutrino is a chemical compounds (TeO 2 ) Majorana particle • underlying mechanism can give insight Thermal detectors are a good into beyond SM physics choice for 0 ν DBD search: • light neutrino mass scale and • excellent energy resolution hierarchy • heavy neutrino • large active mass and • … efficiency/unit cost • fully active source and sensitive volume, no dead-layer M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 4

TeO 2 arrays: state of the art CUORE 10 26 CUORE CUORE is the latest 10 25 in a long progression CUORE-0 [yr] Cuoricino of TeO 2 detectors 10 24 which included two (90% C. L.) large demonstrators: MiDBD 10 23 • Cuoricino 4 crystal array 334 g (2.8x10 24 y) 10 22 73 g • CUORE-0 / 2 t 0 ν 10 21 1 (4.0x10 24 y 34 g combined) 10 20 21 g 6 g 10 19 1990 1995 2000 2005 2010 2015 2020 2025 Running period M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 5

Outline CUORE • TeO 2 and thermal detectors for neutrino-less DBD • CUORE setup ‣ Location ‣ Cryogenic system ‣ Calibration system ‣ Shielding • CUORE roadmap • Analysis procedures ‣ Calibration and detector response ‣ Event selection and topology • Physics results ‣ 0 νββ and lepton number violation ‣ background model ‣ 2 νββ • Conclusions and outlook M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 6

CUORE CUORE Cryogenic Underground Observatory for Rare Events Primary goal: search for 0 νββ decay in 130 Te Detector design: closely packed array of 988 TeO 2 crystals arranged in 19 towers Design parameters: • mass of TeO 2 : 742 kg (206 kg of 130 Te ) • low background aim: 10 -2 c/(keV ⋅ kg ⋅ yr) • target energy resolution: 5 keV FWHM in the Region Of Interest (ROI) • high granularity • deep underground location • strict radio-purity controls on materials and assembly CUORE projected sensitivity (5 years, 90% C.L.): T 1/2 > 9 × 10 25 yr M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 7

The CUORE Collaboration CUORE M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 8

CUORE @ LNGS CUORE 1400 m of rock (~3600 m.w.e.) deep μ ’s: ~3 × 10 -8 / (s ⋅ cm 2 ) • γ ’s: ~0.73 / (s ⋅ cm 2 ) • neutrons: 4 × 10 -6 /(s ⋅ cm 2 ) below 10 MeV • M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 9

CUORE @ LNGS CUORE CUORE M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 10

Underground Laboratory CUORE • Three-story building Y beam Minus-K isolators • Hosting the cryostat supporting structure Main Support Plate Support columns Cryostat H 3 BO 3 panels External lead shield (~70 t) Polyethylene Concrete walls Screw jacks Seismic isolators Movable platform M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 11

The CUORE cryostat CUORE Challenges: • Cool down ~1 ton detector to ~10 mK • Mechanically decoupled for extremely low vibrations Plates : • Low background environment 300 K • Large duty cycle and long term stability 40 K 4 K 600 mK • Cryogen-free cryostat 50 mK 10 mK • Fast Cooling System ( 4 He gas) down to ~50K Top Lead • 5 pulse tubes cryocooler down to ~4K Shield Side Lead • Dilution refrigerator down to operating temperature ~10 mK Shield • Nominal cooling power: 3 μ W @ 10mK Detector Towers • Cryostat total mass ~30 tons • Mass to be cooled < 4K: ~15 tons Bo � om Lead • Mass to be cooled < 50 mK: ~3 tons (Pb, Cu and TeO 2 ) Shield M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 12

Detector calibration system CUORE Challenges: • Provide a uniform calibration of all the CUORE detectors • Deployment of thoriated strings through the cryostat, from room temperature into the detector core • 8 additional tubes can host strings outside the 300K vessel but inside the lead shielding 300 K 4 K Lead Inner string Inner strings Outer strings Outer string External calibration J. S. Cushman et al. The detector calibration system for the CUORE cryogenic bolometer array. Nuclear Instruments and Methods A 844, 32-44 (2017). arxiv:1608.01607 M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 13

Passive shielding CUORE Challenges: • Protect the detectors with a heavy shield against gamma and neutron activity from external sources (~70 tonnes lead + H 3 BO 3 ) • Select materials that don’t contribute themselves to the background level (ancient roman lead and selected NOSV copper) • Cool down inner layers of the shielding to the correct temperature (2.5 tonnes @ 50mK + 5.5 tonnes @ 4K) M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 14

Outline CUORE • TeO 2 and thermal detectors for neutrino-less DBD • CUORE setup ‣ Location ‣ Cryogenic system ‣ Calibration system ‣ Shielding • CUORE roadmap • Analysis procedures ‣ Calibration and detector response ‣ Event selection and topology • Physics results ‣ 0 νββ and lepton number violation ‣ background model ‣ 2 νββ • Conclusions and outlook M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 15

CUORE Roadmap CUORE Cryostat Commissioning 10 Detector Cool down • 8-channels functioning • 300 K —> 4 K in mock-up detector 1 22 days Still plate T [K] • Noise study and • 4 K —> 7 mK in HEX plate mitigation 0.1 MC plate 3.5 days • Stable base • First pulses seen CUORE cool down temperature < 7 mK Start: 2017-01-23 10:00 just after cool- 0 . 01 • Calibration sources down 0 0.5 1 1.5 2 2.5 3 3.5 4 deployment ∆ t [d] Feb 2016 Aug - Oct 2016 Jan 2017 Mar - Apr 2017 Detector pre-operation Detector Installation • Optimisation of all sub-systems • Radon-free • Working temperature and working point environment selection • 1 tower/day, 3 • Noise reduction operators • Read-out testing • Cryostat interfaces • Inner radiation shields M. Biassoni - Revealing the history of the universe with underground particle and nuclear research Tohoku University, Japan - March 7-9, 2019 � 16