CUORE-0, CUORE and Future Opportunity for a 0 nbb Detector in China

1. CUORE-0, CUORE and Future Opportunity for a 0nbb Detector in China Huan Zhong Huang (黄焕中) Department of Physics and Astronomy University of California, Los Angeles 90095 huang@physics.ucla.edu 现代物理研究所 复旦大学 IHEP Beijing Dec 17, 2015

2. Nobel Prize in Physics 2015 Arthur B. McDonald Takaaki Kajita “For the discovery of neutrino oscillations, which shows that neutrinos have mass”

3. 2016 Breakthrough Prize in Fundamental Physics Kam-Biu Luk, Yifang Wang, and the Daya Bay Collaboration Koichiro Nishikawa and the K2K and T2K Collaboration Atsuto Suzuki and the KamLAND Collaboration Arthur B. McDonald and the SNO Collaboration Takaaki Kajita, Yoichiro Suzuki and the SuperK Collaboration For the fundamental discovery and exploration of neutrino oscillations, revealing a new frontier beyond, and possibly far beyond, the standard model of particle physics.

4. Neutrino Mass and Mixing Parameters

5. Neutrino Physics Program Critical Questions for Future Neutrino Physics Program 1) Are neutrinos their own anti-particles? Dirac or Majorana neutrinos Majorana – lepton violation, masses 2) What are the scale of neutrino masses and the hierarchy of the neutrino mass ordering? 3) Do neutrinos violate the CP symmetry and contribute to the matter-antimatter asymmetry? 4) Are there sterile neutrinos?

6. (A,Z) W e– e– W (A,Z+2) (A,Z+1) Even-even nucleus (A,Z) bb (A,Z+2) Double Beta Decay 2 2nbb: T1/2≥ 1018y 1935 M. Goeppert-Mayer (A,Z)(A,Z+2) + 2e– + 2ne

7. 0nbb: T1/2≥ 1025y (A,Z) e W e– n e– W (A,Z+2) n e (A,Z)(A,Z+2) + 2e– Dirac or Majorana Neutrinos? 0 1937 Majorana  neutrino = anti-neutrino Lepton Number violation !

8. Measuring Neutrino Masses • Direct Measurement tritium decays E0 = 18.6 keV <mb> = 2) Effective Majorana Mass <mbb> = ei – CP phase for neutrinos 3) Precise Cosmological Measurement <mS> =

9. Double Beta Decay Candidates Normal beta-decay is energetically forbidden, while double beta-decay from (A,Z)  (A, Z+2) is energetically allowed: (A=even, Z=even) A, Z+1 A, Z+3 0+ A, Z bb 0+ A, Z+2 Some candidates: 48Ca, 70Zn, 76Ge, 80Se, 86Kr, 96Zr, 100Mo, 116Cd, 130Te, 136Xe, 150Nd

10. Candidate for Double beta Decays Q (MeV) Abund.(%)

11. Experimental Search for 0nbb 2nbb decays are irreducible background ! We do not know the relative rate!

12. US-Italy Collaboration CUORE @ LNGS CUORE R&D (Hall C) Underground National Laboratory of Gran Sasso L'Aquila – ITALY 3500 m.w.e. CUORICINO - CUORE (Hall A)

13. CUORE CUORE: Cryogenic Underground Observatory for Rare Events will be a tightly packed array of988 Bolometers-M ~200 kg of 130Te 80 cm • Operated at Gran Sasso laboratory • Special cryostat built w/ selected materials • Cryogen-free dilution refrigerator • Shielded by several lead shields 19 CUORICINO-like towers with 13 planes of 4 crystals each

16. Bolometer Heat sink: ~8-10 mK Thermal coupling: Teflon Thermometer: NTD Ge thermistor Absorber: TeO2 crystal TeO2 Bolometer: Source = Detector

17. Signal from NTD Ge Thermistor

18. CUORE-0 Experiment

19. CUORE-0 Calibration Energy Spectrum 2615 keV 208Tl 911 keV 228Ac 511 keV e+e- 965 keV + 969 keV 228Ac 583 keV 208Tl 1588 keV (228Ac) + 1595 keV 208Tl double escape 2104 keV 208Tl single escape We calibrate the detector using two thoriated tungsten wires source placed in between the outermost cryostat shield and the external lead shield. 2-3 days per month for calibration run.

20. Backgrounds

21. CUORE-0: Stability and Superior Resolution

22. Detector Response Function

23. CUORE-0 Unblinded Result

24. Systematic Errors

25. CUORE-0 Limit on 0vbb T1/2

26. Combining CUORE-0 and CUORICINO Results Published in PRL

27. CUORE Sensitivity Projection Need another factor of 10 to fully cover the IH region !

28. Scaling CUORE and Beyond

29. Future Path • Isotope Enrichment/Detector Mass -- Ton Scale • Te – less expensive, Q = 2528 keV < 2615 keV • Se, Mo and Cd – expensive • Q > 2615 keV • Background Reduction • degraded alpha • gamma – 2615 keV • Particle/Surface Identification from • pulse shaping • scintillation/Cerenkov/phonons

31. USTC Crystal R&D spe Photon-electron peak of 59keV Υ-rays from 241Am Emission Spectrum CaMoO4: 51ph.e/MeV Next Step ZnMoO4 ?

33. Status of 0nbb Experiments

34. Major 0nbb Experiments(scalable to ~1 ton now or planned) 0nbb Experiments -- CUORE 130Te -- MAJORANA/GERDA 76Ge -- EXO 136Xe Essential to Measure 0nbb for Several Elements !!

35. General Comments CUORE-- 130Te -- Excellent Energy Resolution (FWHM 0.3%) -- Cost Effective -- Background Elimination Challenging -- Particle ID Technique GERDA/MAJORANA -- 76Ge -- Ultra-Low Background Possible -- Detector Segmentation and Pulse Shape Analysis Possible -- Very Costly ! EXO/HPXe -- 136Xe -- Easy to Scale Up -- Ba+ Tagging Challenging / FWHM ~1% -- Tracking Could Be Powerful

36. Full estimated range of M0n within QRPA framework and comparison with NSM (higher order currents now included in NSM) – P. Vogel

37. Possible Short Path to the Front Chinese 0vbb Program – 1) Mature technology -- bolometer 2) Technology – Crystal growth 3) Reasonable chance to succeed Need R&D Effort Isotope enrichment /crystal /QA cryogenic technology read-out Shielding and Radon Cu – underground production Material Selection

38. CUORE Collaboration

39. The END