double beta decay experiment Benjamin Schmidt for the CUPID-Mo - PowerPoint PPT Presentation

TAUP 2019, Toyama - 9/11/2019 First data from the CUPID-Mo neutrinoless double beta decay experiment Benjamin Schmidt for the CUPID-Mo Collaboration

The CUPID-Mo collaboration Members from China, France, Germany, Italy, Russia, Ukraine and USA B. Schmidt Toyama, TAUP 2019 - 09/11/2019

Reminder of the bolometric technology – CUORE Reminder -Talk Neutrino#10 Tu, 16.30 New results from the CUORE experiment D E ROI Copper: Thermal Bath Teflon: weak thermal link NTD-Ge thermistor Thermal bath @ 10 mK NTD-Ge • thermistor Excellent energy resolution CUORE • Multiple isotopes can be used in as sensor 750g TeO 2 bolometric measurement C(T) a T 3 Si heater crystals • Ton scale cryogenic infrastructure at LNGS • Background limited 3 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

CUPID = CUORE Upgrade with Particle Identification Other isotopes CUORE: Experimental sensitivity with Bg 214 Bi 208 Tl Idea: a | b & g particle discrimination via detection of Cherenkov or Scintillation light Light yield from scintillating • compounds like Li 2 MoO 4 is > 1 keV at Q bb No prominent g line from natural • decay chains above 2614.5 keV No Background ( 208 Tl) See also arXiv:1907.09376 4 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

CUPID-Mo experiment Operated at LSM by the EDELWEISS/CUPID-Mo collaborations, • follow up of the LUMINEU experiment 20 x ~210 g cylindrical Li 2 MoO 4 crystals enriched to ~97% in • 100 Mo, dimensions: ø 44 mm x 45 mm Ge wafer with SiO anti-reflective coating as light detector • Ge-NTD (on both Li 2 MoO 4 and Ge light detector) • Cu holder (citric-acid etching for surface treatment) • 3M Vikutui reflectors • enhance LY to ~0.7 keV/MeV (peaked at ~600 nm) First data: • arXiv:1909.02994 Commissioning & setup March/April 2019 • Physics data taking since April – June 2019 • 5 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

CUPID-Mo commissioning 20 Li 2 MoO 4 , 19 LD, 18 Pulser lines Example LMO avg. pulse • operational @ 20.7 mK Median Baseline resolutions • 19/20 LMO: 1.96 keV 18/19 LD: 148 eV > 99.9% alpha separation expected Li 2 MoO 4 pulse characteristics • 25 ms rise, 300 ms decay time (20.7 mK) • Ge light detector • 4 ms rise * , 9 ms • decay time Example Heat/Light * limited by sampling & AC bias separation Summed energy resolution • Li 2 MoO 4 : 5.3 keV FWHM * ( * bias from gain stabilization) Good uniformity/performance • suitable for larger arrays! arXiv:1909.02994 6 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

CUPID-Mo first data – U/Th calibration 208 Tl & ~10 days of e +- U/Th calibration 214 Bi 228 Ac 214 Pb 228 Ac 214 Bi 208 Tl 214 Bi DE 214 Bi 208 Tl 214 Bi SE Optimum Filter analysis tuned to mitigate • surplus microphonics noise 214 Bi Data quality cuts: • Data quality selection on unstable • cryogenic periods Basic cuts: pile up rejection and • anticoincidence cuts Light Yield cut for b/g events • Pulse shape cut on 4 normalized shape • variables Characteristic resolution @2614.5 keV • 6.7 keV FWHM, H. mean 19/20 channels 7 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

Resolution & Energy scaling of CUPID-Mo detectors Harm. Mean: DE 6.7 keV FWHM 214 Bi Spread (RMS): 1.9 keV 214 Bi 208 Tl 214 Bi 228 Ac 214 Bi 208 Tl 214 Pb Expected energy resolution (FWHM) at Q bb 3034 keV: • (7.7 ± 0.4) keV Simultaneous UEML fit (common multi-Compton ratio • & background, 19 individual resolutions) 8 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

CUPID-Mo - First physics data 99 Mo CUPID-Mo 0.5 kg*yr Optimum Filter based Amplitude estimate • e +- 60 Co 60 Co Thermal gain stabiliation on 208 Tl 214 Bi 214 Pb 40 K (calibration data) Data quality cuts: • 212 Pb 208 Tl Data quality selection on unstable • cryogenic periods (4%) 208 Tl Basic cuts: pile up rejection and • anticoincidence cuts Light Yield cut for b / g events • Pulse shape cuts on 4 normalized • pulse shape parameters (Risetime, Decaytime, Pulse maximum, Baseline slope) Energy resolution ~ (7.8 ± 0.9) keV FWHM • @2614.5 keV, 19/20 channels 9 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

Energy scale and resolution (FWHM) physics data 208 Tl 208 Tl 60 Co 40 K 60 Co 60 Co 60 Co 40 K 99 Mo 99 Mo Energy resolution (FWHM) at Q bb 3034 keV: • 208 Tl 60 Co 40 K (6.6 ± 1.1) keV 99 Mo Uncertainty and bias on energy scale from 2nd order • Q bb 60 Co poynomial fit. — > D E = (0.0 ± 1.6) keV 10 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

CUPID-Mo – The region of interest Exposure: 0.5 kg*yr (~2 month) • ~5 times the LUMINEU Li 2 MoO 4 statistics 100 Mo with shortest T 1/2 of all 2 nbb isotopes: (6.90 ± 0.15 (stat.) ± 0.37 (syst.)) * 10 18 yr Eur. Phys. J. C (2017) 77: 785 • Spectrum dominated by 2 nbb decay above ~ 500 keV (expected) (new 2 nbb half-live evaluation in preparation) First part of physics data 99 Mo 99 Mo a Energy & cuts ( > 2.8 MeV ) Summed spectrum: 0.5 kg*yr g Energy & cuts 60 Co 60 Co 40 K 210 Po 40 K 208 Tl 208 Tl Light Yield 234 U/ 226 Ra ROI 3034 keV cut B. Schmidt Toyama, TAUP 2019 - 09/11/2019 11

100 MoO 4 Radiopurity of Li 2 Minimal cuts (pile-up cut)  • Uranium 210 Po > 97% signal acceptance 218 Po 238 U 234 Th + s = 5.2 keV Estimate contamination in ± 15 keV window • 226 Ra 210 Po ( 210 Pb) ~ 158(3) m Bq/kg • 222 Rn 190 Pt 0.37(15) m Bq/kg • 230 Th • degraded alphas [3,4] MeV: 0.16(2) counts/kev/kg/yr • No bg subtraction yet; 210 Po Thorium expect up to 2 accidental 228 Th counts 224 Ra 232 Th Contamination for both Th- and U-series are ~10 x better than assumed in CUPID preCDR 212 Bi ( arXiv: 1907.09376) U: ~0.5 m Bq/kg Th: ~0.3 m Bq/kg 12 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

Bg for 100 Mo in CUPID-Mo & beyond Degraded alphas: • 0.16(2) counts/keV/kg/yr • Rejection by Light Yield: Detector performance compatible with > 99.9% • gaussian separation Will be further studied from data with high statistics AmBe calibration Natural radioactivity - Surface & bulk: • 214 Bi beta (3.3 MeV Q-value) 208 Tl beta (5 MeV Q-value) Th chain: 232,228 Th ~ 0.3 m Bq/kg (bulk) • U chain: 238,234 U, 230 Th, 226 Ra ~ 0.5 m Bq/kg (bulk) • Further surface & bulk contaminations – to be studied with Geant4 MC • --> Background model fit CUPID-Mo Random gamma pile-up ( 100 Mo 2 nbb , …) • ~ 0.5 kg*yr physics data r • 208 Tl 2615 keV NTD light detectors with Neganov-Luke amplification or TES/MMC sensors can • give >10x improvement on T R Environmental muon/neutron bg • 100 Mo Q bb : 3034 keV (to be studied in more detail AmBe data) 7 Li+n --> 8 Li --> 8 Be + b (16 MeV endpoint) --> a+a • Cosmogenic activation/ muons & muon-induced events • 13 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

CUPID-Mo - Outlook Now: accumulated > 1 kg*yr of physics data • T 1/2 > 3*10 23 yr at 90% C.L with • ~0.5 kg*yr exposure (~0.27 kg*yr of 100 Mo), 81% signal acceptance Confirmed: Bolometric performance & • reproducibility, exceeded expectations for radiopurity (bulk) Next: Use Geant4 MC and data to build a • detailed background model NEMO 3 limit (~ 7 kg 100 Mo , 5 yr) Introduce data blinding • Phys. Rev. D 92(2015) 072011 T 1/2 > 1.1 x 10 24 yr Optimize 0 nbb analysis cuts • Goal : Reach > 2 kg * yr of physics • exposure, ~6 month with 19/20 detectors, CUPID-Mo accumulated 90% analysis efficiency Analyzed – 0.5 kg*yr 75% 0nbb containment 14 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

CUPID with 100 Mo Goal: Discover 0 nbb for effective m bb masses in the inverted hierarchy range; Explore the prospects to probe beyond arXiv:1907.09376 See Talk Neutrino#17 We,18.00 CUPID: CUORE Upgrade with Particle ID Details later in this session: Talk Neutrino#17 CUPID: CUORE Upgrade with Particle ID 15 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

Thank you – Toyama/TAUP 2019 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

Backup B. Schmidt Toyama, TAUP 2019 - 09/11/2019

CUPID-Mo – The Bg spectrum translated to a limit Base cuts e = (97.1 ± 0.4)% • Rise + Decay time (unfiltered Pulseshape) e = (94.7 ± 0.1) % (LY + NormDelay + NormBaseline) e = (88.3 ± 0.3)% Total efficiency of all cuts • e = ( 81.1 ± 0.5)% Non blind analysis • NMEs: JHEP02 (2013) 025 Nucl. Phys. A 818, 139 (2009) T 1/2 > 3*10 23 yr at 90% C.L • Phys. Rev. C 87, 045501 (2013) Phys. Rev. C 87, 064302 (2014) Limit on m bb : 715 - 1190 meV • Phys. Rev. C 91, 034304 (2015) Phys. Rev. C 91, 024613 (2015) dependent on Nuclear Matrix Element Phys. Rev. C 91, 024309 (2015) Phys. Rev. C 91, 024316 (2015) Phys. Rev. Lett. 105, 252503 (2010) Phys. Rev. Lett. 111, 142501 (2013) 18 B. Schmidt Toyama, TAUP 2019 - 09/11/2019

Evaluation of efficiencies - BaseCuts & M1 The alpha region - significant • 210 Pb/ 210 Po contamination && no line of sight between detectors  should all be M1 events Evaluate the most basic • efficiencies on this peak Efficiency of • SingleTrigger • !Filter_SuspectedPulser • Multiplicity1 cut • 1436/1479.0 counts • e = (97.1 ± 0.4)% 19 B. Schmidt Toyama, TAUP 2019 - 09/11/2019