1. 1 TAUP - September 7, 2015S. Blot Investigating ββ decay with NEMO-3 and SuperNEMO Summer Blot, on behalf of the NEMO-3 and SuperNEMO experiments 7 September 2015 Outline Review of double beta decay Recent results from NEMO-3 Status of SuperNEMO Summary

2. 0νββ decay  BSM process that violates ΔL conversation by 2 units  Can be mediated by: Light Majorana ν, (V+A) current, SUSY  Observed final state identical to 2νββ 2 TAUP - September 7, 2015S. Blot 2νββ Arbitrary units ΣE e = Q ββ 0νββ ΣE e < Q ββ 2νββ decay  Occurs if β-decay is forbidden or highly suppressed (35 isotopes)  2 nd order weak process in the Standard Model (SM) (T ½ ~10 18- 21 yrs)  Detect 2 electrons with continuous ΣE ΤΟΤ ( ν e ’s escape detection)

3. 3 TAUP - September 7, 2015S. Blot Why search for 0νββ decay?  Observation of 0νββ decay would provide first evidence that lepton number is not conserved (LPV)  Test Dirac vs Majorana nature of the neutrino  If underlying mechanism is light Majorana neutrino exchange, can determine mass scale of neutrino Experimen t Theoretical input New physics

4. The NEMO-3 experiment 4 TAUP - September 7, 2015S. Blot  Operated from Feb 2003–Jan 2011  Modane Underground Laboratory (LSM)  Passive detector design  Source ≠ Detector  Cylindrical geometry (R,φ,z)  7 different isotopes investigated  Separate tracker-calorimeter systems  Ability to reconstruct full kinematics of final state  Can disentangle underlying 0νββ mechanisms  Measure backgrounds in situ

5. The NEMO-3 experiment 5 TAUP - September 7, 2015S. Blot Source foils Central tower Inner calo. wall Outer calo. wall Trackin g volume φ R x z y x y z  Operated from Feb 2003–Jan 2011  Modane Underground Laboratory (LSM)  Passive detector design  Source ≠ Detector  Cylindrical geometry (R,φ,z)  7 different isotopes investigated  Separate tracker-calorimeter systems  Ability to reconstruct full kinematics of final state  Can disentangle underlying 0νββ mechanisms  Measure backgrounds in situ

6. The NEMO-3 detector 6 TAUP - September 7, 2015S. Blot  ~10 kg of ββ-decay isotopes  100 Mo, 82 Se, 130 Tl, 116 Cd, 150 Nd, 96 Zr and 48 Ca  Produced as thin foils 30- 60mg/cm 2  Typically 2.5 in height, 63-65 mm wide  ~10 kg of ββ-decay isotopes  100 Mo, 82 Se, 130 Tl, 116 Cd, 150 Nd, 96 Zr and 48 Ca  Produced as thin foils 30- 60mg/cm 2  Typically 2.5 in height, 63-65 mm wide  Tracking chamber (both sides of foil)  6180 Geiger cells (50μm) operating in gas mixture of 95 % He, 4 % alcohol, 1 % Ar and 0.1 % H 2 O  Vertex resolution σ XY ~3 mm, σ Z ~10mm  Tracking chamber (both sides of foil)  6180 Geiger cells (50μm) operating in gas mixture of 95 % He, 4 % alcohol, 1 % Ar and 0.1 % H 2 O  Vertex resolution σ XY ~3 mm, σ Z ~10mm  Calorimeter (top, bottom, in and out)  1940 optical modules  3” and 5” PMTs coupled to polystyrene scintillator blocks  σ E ~14-17 % (FWHM), σ t ~250 ps (1σ) electrons @1 MeV  Calorimeter (top, bottom, in and out)  1940 optical modules  3” and 5” PMTs coupled to polystyrene scintillator blocks  σ E ~14-17 % (FWHM), σ t ~250 ps (1σ) electrons @1 MeV

7. 7 TAUP - September 7, 2015S. Blot The NEMO-3 experiment – ββ-decay sources  Observation of 0νββ must be confirmed in multiple isotopes  NEMO-3 (SuperNEMO) designed with this in mind  Largest mass with 100 Mo (6.9 kg) and 82 Se (0.93 kg)

8. 8 TAUP - September 7, 2015S. Blot  Select events with two electrons outgoing from the foil with common vertex  Measure all relevant kinematics to reject backgrounds and investigate 0νββ topology if observed B cosθ E1t1E1t1 E2t2E2t2 l2l2 l1l1 Mass mechanism Right-handed Current cosθ between electrons energy difference between electrons (MeV) Theoretical Reconstructed Theoretical Reconstructed Mass mechanism Right-handed Current -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 0 0.5 1 1.5 2 2.5 3 1 0.8 0.6 0.4 0.2 0 1 0.8 0.6 0.4 0.2 0 Events 1 0.8 0.6 0.4 0.2 0 Events 1 0.8 0.6 0.4 0.2 0 The NEMO-3 experiment – Detection principle

9. 9 TAUP - September 7, 2015S. Blot Backgrounds  External backgrounds from neutrons capture, producing high energy γ-rays  Reduced with 4800m water equivalent overburden and extensive passive shielding (wood, iron, borated water)  Radon induced backgrounds  Reduced by tagging α-particles from 214 Bi- 214 Po cascade  Internal background decays  e.g. Single β-decay + Møller scattering + conversion electron + γ + Compton scattering  2νββ decay  Irreducible – must measure rate with high precision γ γ Internal backgrounds External backgrounds Use background topology to measure expected rates

10. 10 TAUP - September 7, 2015S. Blot Background channels  External background channels (top right) identified by distinct time sequence of scintillator hits in the event (t i << t j )  Single electron channel (bottom right) provides channel to measure isotopes which undergo single β- decay [arxiv:1506.05825] External e - γ Single e -

11. Latest NEMO-3 Results – 100 Mo 11 TAUP - September 7, 2015S. Blot  Best 0νββ sensitivity in NEMO-3 using 34.7 kgy 100 Mo  No significant excess of data over expected background in region of interest: E TOT = [2.8-3.2] MeV  Limits derived on T ½ (0νββ) for various processes Phys. Rev D 89, 111101 (2014). [arxiv:1506.05825] Phys. Rev D 89, 111101 (2014). [arxiv:1506.05825] < 0.33-0.62 eV

12. Comparison to other isotopes 12 TAUP - September 7, 2015S. Blot  Most stringent half-life limit on 0νββ with 100 Mo from NEMO-3 (top)  Translation into effective neutrino mass also shown (bottom)  See [arxiv:1506.05825] for references to other isotope results

13. Other results from NEMO-3 13 TAUP - September 7, 2015S. Blot Updated results coming soon…  Best results of 2νββ T½ measurements for all 7 isotopes investigated  Best 0νββ decay limits for many as well  See backup slides for details or J.Phys.Conf.Series 375 (2012) 042011 T ½ 2ν ( 100 Mo )= 7.16 ± 0.01 stat ± 0.54 syst

14. Moving towards SuperNEMO  SuperNEMO shares the same detector design principles as NEMO-3  Modular in design  first module (of 20 total) is the demonstrator  Demonstrator will house 7kg of 82 Se and with 2.5y will reach sensitivity of ~ 0.2 – 0.4 eV 14 TAUP - September 7, 2015S. Blot *Values in table correspond to the full 20 modules of SuperNEMO 0ν0ν 0ν0ν Full SuperNEMO: m ββ ~ 0.04-0.1 eV

15. The SuperNEMO detector 15 TAUP - September 7, 2015S. Blot  7kg of 82 Se per module ( 150 Nd purification studies ongoing, 48 Ca also possible)  Thin foils with better radiopurity  Factor of x10 decrease in 208 Tl contamination and x30 decrease in 214 Bi  7kg of 82 Se per module ( 150 Nd purification studies ongoing, 48 Ca also possible)  Thin foils with better radiopurity  Factor of x10 decrease in 208 Tl contamination and x30 decrease in 214 Bi  Tracking chamber (both sides of foil)  Wire chamber operating in Geiger mode  Tracking chamber (both sides of foil)  Wire chamber operating in Geiger mode  Calorimeter: two main walls  5” and 8” PMTs coupled to scintillator block with optimized geometry  σ E ~ 7.8 % (FWHM) for electrons @1 MeV  Calorimeter: two main walls  5” and 8” PMTs coupled to scintillator block with optimized geometry  σ E ~ 7.8 % (FWHM) for electrons @1 MeV B

16. 16 TAUP - September 7, 2015S. Blot SuperNEMO demonstrator status – source foils Source foil mounting test  ~25% of source foil produced for demonstrator ( 82 Se)  Radio-purity measurements underway using the dedicated BiPo detector The BiPo detector

17. 17 TAUP - September 7, 2015S. Blot Populating a C-section Wiring robot for cell production SuperNEMO demonstrator status – tracker  First half of tracker complete  First quarter (aka C0) commissioned, ready for shipment to LSM  98.4% of cells fully operational! (504 total)  Radon tests for C1 underway, commissioning to follow Bottom seal plate First tracks in C0

18. 18 TAUP - September 7, 2015S. Blot SuperNEMO demonstrator status – calorimeter  Production and testing of optical modules is well underway  Energy resolution meeting design specifications Optical module production and testing

19. 19 TAUP - September 7, 2015S. Blot Radon emanation chamber SuperNEMO demonstrator status – radiopurity  All materials screened for radiopurity with HPGe detectors and radon emanation chamber  Radon concentration line to measure Rn in tracker gas (Target < 0.15 mBq/m 3)  Preliminary measurements of radon in C-sections are very promising!! Radon centration line

20. 20 TAUP - September 7, 2015S. Blot SuperNEMO demonstrator status – software  Many tools already implemented and validated  Event generation and simulation of detector components  Event reconstruction and particle ID  Improved tracking algorithms  α –particle ID  Advanced γ tracking algorithm

21. 21 TAUP - September 7, 2015S. Blot Support frame installed at LSM C-section ready for transport to LSM SuperNEMO demonstrator - integration Optical module production underway SuperNEMO Demonstrator starting to take shape Commissionin g by 2016

22. Sensitivity of next generation 0νββ experiments 22 TAUP - September 7, 2015S. Blot = | m 1 |U e1 | 2 +m 2 |U e2 | 2 e i α + m 3 |U e3 | 2 e i β | SNO+, SuperNEMO, CURORE< EXO+, GERDA, KAMLAND-Zen+ (2017– ) SNO+, SuperNEMO, CURORE< EXO+, GERDA, KAMLAND-Zen+ (2017– ) SNO+ ungraded, nEXO, Super- KamLAND-Zen P. Guzowski et al., Submitted to PRD (2015). arXiv:1504.03600v1 [hep-ex] Current best limit at m ββ < 130 - 310 meV (90% CL) Assumes 3 neutrino mixing model

23. Summary  The NEMO-3/SuperNEMO experiments offer a unique way to search for 0νββ decay and disentangle underlying mechanisms  Analysis of full data set from NEMO-3 is ongoing  Best results with 100 Mo yield m ββ < 0.33-0.62 eV Coming soon: new results from 82 Se, 116 Cd 150 Nd, 96 Zr and 48 Ca 23 TAUP - September 7, 2015S. Blot Thank you for your attention!  Construction of SuperNEMO demonstrator is well underway  Many of the most challenging design specifications have been achieved or are very close to being met  Commissioning of demonstrator should begin next year (2016)  Goal is to reach m ββ < 0.2-0.4 eV in just 2.5 years of running

24. BACKUP SLIDES 24 TAUP - September 7, 2015S. Blot

25. 25 TAUP - September 7, 2015S. Blot Dirac vs Majorana Schechter-Valle theorem Image from Neutrino Physics Kai Zuber, IoP Publishing 2004

26. Experimental considerations for 0νββ 26 DESY seminar 2015S. Blot  Choice of isotope  Large G 0ν and M 0ν for shorter T 1/2  Large Q ββ for background rejection  Large mass of isotope of interest  Enrichment, purification, abundance  Detector design  Good energy resolution  Radio-pure materials  Active or passive  Choice of location  Experiments underground and protected by many layers of passive and active shielding to protect from cosmic muon spallation, uranium fission, etc GERDA NEMO-3 SuperNEMO SNO+

27. NEMO-3 tracker 27 DESY seminar 2015S. Blot  Wire tracking chamber with 6180 cells operating in Geiger mode  95% He, 4% alcohol, 1% Ar, 0.1% H 2 O  Vertex resolution: σ XY ~ 3 mm, σ Z ~ 10 mm  25 G magnetic field for discrimination between e + /e - Ground wire Anode Cathode ring Source foil Gaps for top/bottom calorimeter Single tracker cell anatomy 4-2-3 layout on each side of source foil

28. NEMO-3 calorimeter 28 DESY seminar 2015S. Blot  1940 optical modules  3” and 5” low-radioactivity PMTs coupled to large (10x10x10) scintillator blocks  ~15% / √E @ 1 MeV  Dedicated studies for PMT monitoring to ensure high quality modules used in analysis Optical module anatomy PMT base electronics Magnetic shielding Light-tight sleeve PMT Interface light guide Light guide Iron ring Aluminized Mylar coating Particle entrance Scintillator block External wall of sector Optical fibre 0 50 100 mm PMT stability monitoring

29. NEMO-3 calibrations 29 DESY seminar 2015S. Blot  Monthly absolute calibration runs with 207 Bi sources + runs with 90 Sr source for calibrating up to 3 MeV  Check PMT stability with daily laser survey (82% of PMTs stable for entire lifetime of experiment) Laser survey validation 207 Bi C.E. peaks 90 Sr ( 90 Y) endpoint

30. 30 TAUP - September 7, 2015S. Blot 1e1α event display Measuring backgrounds: 214 Bi- 214 Po cascade  Electronics store Geiger hits information up to 700μs after event trigger  Tag 214 Bi- 214 Po cascades with one electron and one cluster of delayed Geiger hits (α) 214 Po half-life is 164.3 μs arxiv:1506.05825

31. Crossing electron 31 TAUP - September 7, 2015S. Blot Measuring backgrounds: Crossing electrons  High energy external γ-flux can produce e + e - pairs in foil  Use passive shielding to reject most events (slide 9)  Use calo timing information to tag and characterize external events NIM A 606: 449-465, 2009

32. 32 TAUP - September 7, 2015S. Blot Measuring backgrounds: electron + gammas  Many internal background decay to excited states of their daughter isotopes  Tag γ rays emitted in de-excitation to identify these backgrounds  Channel selects one electron and N scintillator hits without tracks pointing to them 100 Mo 1e2γ & 1e3γ arxiv:1506.05825

33. Results from NEMO-3 33 TAUP - September 7, 2015S. Blot New results soon for 150 Nd, 48 Ca, 116 Cd and 82 Se for full exposure!

34. 100 Mo 0νββ result 34 TAUP - September 7, 2015S. Blot  Event break-down  Dominant systematic is absolute normalization on 0νββ efficiency