1. Experimental status of the Double Beta Decay Marisa Pedretti INFN Milano Bicocca

2. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren2 OUTLOOK OF THIS TALK OUTLOOK OF THIS TALK - Neutrinoless Double Beta Decay and Neutrino Physics - Requirements for a competitive experiment - Present situation of 0 DBD - Future experiments

3. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren3 two electrons each with a continuous spectrum and a monochromatic sum energy new physics beyond the SM Double Beta Decay Signature Double Beta Decay Signature 0 DBD: (A,Z)  (A,Z+2) + 2e -  2 DBD: (A,Z)  (A,Z+2) + 2e - + 2 e  Allowed by SM sum electron energy / Q 2 neutrinos Double Beta Decay continuous spectrum Neutrinoless Double Beta Decay peak enlarged by the detector energy resolution

4. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren4 0 DBD and neutrino physics 0 DBD and neutrino physics parameter containing the physics what the nuclear theorists try to calculate what the experimentalists try to measure How 0 DBD is connected to neutrino mixing matrix and masses?  M   = | |U e1 | 2 M 1 + e i   | U e2 | 2 M 2 + e i   |U e3 | 2 M 3 |  = G(Q,Z) |M nucl | 2  M   2 neutrinoless Double Beta Decay rate Phase space Nuclear matrix elements Effective Majorana mass In case of dominant mass mechanism:

5. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren5  M   = | |U e1 | 2 M 1 + e i   | U e2 | 2 M 2 + e i   |U e3 | 2 M 3 | 0 DBD and neutrino physics 0 DBD and neutrino physics S. Pascoli, S. T. Petcov and T. Schwetz, hep-ph/0505226 76 Ge claim excluded by CUORICINO, NEMO3 Inverted Hierarchy Normal Hierarchy Quasi Degenerate

6. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren6 Target sensitivity Target sensitivity S. Pascoli, S. T. Petcov and T. Schwetz, hep-ph/0505226 Approach the inverted hierarchy region in a first phase (  m  >50 meV) Exclude the inverted hierarchy region in a second phase (  m  >15 meV) Future target sensitivities can be divided in two phases:

7. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren7 Target sensitivity Target sensitivity S. Pascoli, S. T. Petcov and T. Schwetz, hep-ph/0505226 15 meV 50 meV 500 meV 3 different value of neutrino mass can be seen as future milestones:

8. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren8 In order to give an idea of the amazing challenge of the future sensitivity targhet: Target sensitivity Target sensitivity S. Pascoli, S. T. Petcov and T. Schwetz, hep-ph/0505226 15 meV 50 meV 500 meV Counts / y ton Ge natural Ge enriched TeO 2 natural TeO 2 enriched Rodin et al. Civitarese Suhonen new calculation 50599 4111085 1519 Nucl. Phys. A 729, 867 (2003) 37434575 Counts / y ton Ge natural Ge enriched TeO 2 natural TeO 2 enriched Rodin et al. new calculation Civitarese Suhonen Nucl. Phys. A 729, 867 (2003) 0.515.99 4.1110.85 0.374.35.7 15 new calculation Counts / y ton Ge natural Ge enriched TeO 2 natural TeO 2 enriched Rodin et al. Civitarese Suhonen Nucl. Phys. A 729, 867 (2003) 0.0460.54 0.0330.39 0.370.98 0.521.37 Sensitive masses at the 1 ton scale are required The order magnitude of the Bkg is ≤ 1 c / y ton

9. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren9 Experimental parameters Experimental parameters How experimental parameters are connected to the Majorana mass sensitivity of experiment? sensitivity F: lifetime corresponding to the minimum detectable number of events over background at a given confidence level background level F  (MT / b  E) 1/2 energy resolution live time source mass F  MT importance of the nuclide choice (but large uncertainty due to nuclear physics) sensitivity to  m   (F/Q |M nucl | 2 ) 1/2  1 bEbE MT Q 1/2 1/4 |M nucl | b  0 b = 0 b: specific background coefficient [counts/(keV kg y)]

10. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren10 Background Sources Background Sources Common to all tecnhiques and experiments Cooperation (in Europe, ILIAS)  Natural radioactivity of materials (source itself, surrounding structures)  Neutrons  Cosmogenic induced activity (long living)  2 Double Beta Decay Levels of < 1  Bq / kg are required for some materials at the ton scale Purification techniques Quality control procedure to establish: diagnostic is a problem by itself (traditional gamma counting not sufficient) Improve alternative techniques: - ICPMS - Neutron Activation Analysis - “Ad hoc” bolometers for alpha self-counting - Full prototype used to measure contamination (BiPo detector) Two main sources - Activity in the rock and in surrounding materials ( , n) processes  [0,10] MeV spectrum  can be shielded - High-energy  induced complicated problem  depth  appropriate shielding / coincidence techniques  reliable simulations  “Ad hoc” experiments at muon accelerators could be useful Choice of materials Storage of materials underground Partial or full detector realization underground (Ge diodes) Crucial for all experiments and techniques cooperation (in Europe, ILIAS) Critical in the low energy resolution techniques energy resolution [%] 1000 100 10 1 0.1 0.01 0.001 sensitivity to  m  [meV] 12 3 4 present sensitivity Inverted hierarchy A challenge for the space-resolving techniques, which normally have low energy resolution (~ 10 %)

11. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren11 Choice of the nuclide Choice of the nuclide Isotopic abundance (%) 48 Ca 76 Ge 82 Se 96 Zr 100 Mo 116 Cd 130 Te 136 Xe 150 Nd 0 20 40 Transition energy (MeV) 48 Ca 76 Ge 82 Se 96 Zr 100 Mo 116 Cd 130 Te 136 Xe 150 Nd 2 3 4 5 end of  region Nuclear Matrix Element new calculation

12. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren12 High energy resolution (<2%) No tracking capability Easy to reject 2 DBD background Low energy resolution (>2%) Tracking / topology capability Easy to approach zero backround (with the exception of 2 DBD component ) e-e- e-e- Source  Detector Easy to approach the ton scale e-e- e-e- source detector Source  Detector Easy to get tracking capability Experimental techniques Experimental techniques CUORE - 130 Te Array of low temperature natural TeO 2 calorimeters operated at 10 mK First step: 200 Kg (2011) – LNGS Proved energy resolution: 0.25 % FWHM GERDA - 76 Ge Array of enriched Ge diodes operated in liquid nitrogen or liquid argon First phase: 18 Kg; second phase: 40 Kg - LNGS Proved energy resolution: 0.16 % FWHM MAJORANA - 76 Ge Array of enriched Ge diodes operated in conventional Cu cryostats Based on 60 Kg modules; first step: 2x60 Kg modules Proved energy resolution: 0.16 % FWHM COBRA - 116 Cd competing candidate – 9  isotopes Array of 116 Cd enriched CdZnTe of semiconductor detectors at room temperatures Final aim: 117 kg of 116 Cd Small scale prototype at LNGS Proved energy resolution: 1.9% FWHM Even though these experiments do not have tracking capability, some space information helps in reducing the background thanks to: GRANULARITY of the basic design - CUORE: 988 closed packed individual bolometers - COBRA: 64,000 closed packed individual detectors - MAJORANA: 57 closed packed individual diodes per module PULSE SHAPE DISCRIMINATION - GERDA / MAJORANA can separate single / multi site events SEGMENTATION and PIXELLIZATION Granularity can be achieved through electrodes segmentation  R&D in progress for GERDA, MAJORANA, COBRA SURFACE SENSITIVITY in bolometers - R&D in progress in CUORE against energy-degraded  and  background Simultaneous LIGHT and PHONON detection in bolometers - R&D in progress in CUORE-like detectors for  /  rejection

13. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren13 e-e- e-e- Source  Detector Easy to approach the ton scale e-e- e-e- source detector Source  Detector Easy to get tracking capability High energy resolution (<2%) No tracking capability Easy to reject 2 DBD background Low energy resolution (>2%) Tracking capability Easy to approach zero backround (with the exception of 2 DBD component) SUPERNEMO - 82 Se or 150 Nd Modules with source foils, tracking and calorimetric sections, magnetic field for charge sign Possible configuration: 20 modules with 5 kg source for each module  100 Kg Energy resolution: 4 % FWHM MOON - 100 Mo or 82 Se or 150 Nd Multilayer plastic scintillators interleaved with source foils + tracking section MOON-1 prototype without tracking section Proved energy resolution: 6.8 % FWHM Final target: collect 5 y x ton DCBA - 82 Se or 150 Nd Momentum analyzer for  particles consisting of source foils into a drift chamber with magnetic field Prototype under construction: Nd 2 O 3 foils  1.2 g of 150 Nd Space resolution ~ 0.5 mm; energy resolution 11% FWHM at 1 MeV  6 % FWHM at 3 MeV Final target: 10 modules with 84 m 2 source foil for module (126 through 330 Kg total mass) Experimental techniques Experimental techniques

14. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren14 e-e- e-e- Source  Detector Easy to approach the ton scale e-e- e-e- source detector Source  Detector Easy to get tracking capability High energy resolution (<2%) No tracking capability Easy to reject 2 DBD background Low energy resolution (>2%) Tracking / topology capability Easy to approach zero backround (with the exception of 2 DBD component) EXO – 136 Xe TPC of enriched liquid Xenon Event position and topology; in prospect, tagging of Ba single ion (DBD daughter)  only 2 DBD background Next step (EXO-200: funded, under construction): 200 kg – will be operated in the WIPP facility Proved energy resolution: 3.3 % FWHM Experimental techniques Experimental techniques

15. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren15 e-e- e-e- Source  Detector Easy to approach the ton scale e-e- e-e- source detector Source  Detector Easy to get tracking capability High energy resolution (<2%) No tracking capability Easy to reject 2 DBD background Low energy resolution (>2%) Tracking / topology capability Easy to approach zero backround (with the exception of 2 DBD component) SNO++ – 150 Nd Liquid scintillator loaded with Nd 1000Ton in SNO detector. Total isotope mass 560 kg. Probable energy resolution: 6.7 % FWHM This experiment compensates the low energy resolution with the huge statistic Experimental techniques Experimental techniques

16. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren16 Source = Detector Well known Ge diodes technology  5 Ge diodes with a total statistic of 10.9 kg - ( 86%) 76 Ge  location: Underground Gran Sasso Laboratory (Italy)  detectors shielded with lead and N 2 fluxed  Reduction of Bkg with Pulse Shape Analysis (PSA) (factor 5) Multi-site events identification (gamma bkg) 7.6  10 25 76 Ge nuclei Heidelberg Moscow Exp and the 0 DBD claim Heidelberg Moscow Exp and the 0 DBD claim December 2001, 4 authors (KDHK) of HM collaboration claim the 0 DBD of 76 Ge Spectrum with 71.7 kgy

17. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren17 KKDC claim: m ee = 0.1 - 0.9 eV (0.44 eV b.v.)   1/2 0 (y) = (0.69 – 4.81)  10 25 y (1.19  10 25 y b.v.) (99,9973 % c.l.  4.2 σ) H.V. Klapdor-Kleingrothaus et al. NIM. A 522(2004)371 most probable value: 28.7 in 71.7 kg y exposition Skepticism of scientific community Klapdor-Kleingrothaus HV hep-ph/0205228 H.L. Harney, hep-ph/0205293 Independent answers of authors Klapdor-Kleingrothaus HV et al., NIM A510(2003)281 Klapdor-Kleingrothaus et al., NIM A 522(2004)371 Other articles Aalseth CE et al., Mod. Phys. Lett. A 17 (2002) 1475 Feruglio F et al., Nucl. Phys. B 637 (2002) 345 Zdezenko Yu G et al., Phys. Lett. B546(2002)206 Comments and analysis HD-M data Heidelberg Moscow Exp and the 0 DBD claim Heidelberg Moscow Exp and the 0 DBD claim Not totally accepted result unrecognized peaks dimension of analyzed energy window

18. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren18 Experiments From the ApPEC roadmap…

19. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren19 Running experiments Running experiments

20. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren20 NEMO 3 (Neutrino Ettore Majorana Experiment) NEMO 3 (Neutrino Ettore Majorana Experiment) Other sources → 100 Mo Q  = 3034 keV Detector: tracking detector with different sources Energy resolution: 8% @ Qvalue Location: Modane Underground Laboratory (France) Bckg  sources   thickness  mg/cm 2 ) 82 Se (0,93 kg)  Multi-source detector

21. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren21 NEMO 3 (Neutrino Ettore Majorana Experiment) NEMO 3 (Neutrino Ettore Majorana Experiment) 1 Source plane 2 Tracking volume (3-D readout wire drift chamber with 6180 cells) 3 Calorimeter volume (1940 plastic scintillator block) 2 spectrum Vertex  event E 1 +E 2 = 2088 keV  t= 0.22 ns (  vertex)  = 2.1 mm E1E1 E2E2 e-e- e-e-

22. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren22 NEMO 3 (Neutrino Ettore Majorana Experiment) NEMO 3 (Neutrino Ettore Majorana Experiment) 1 Source plane 2 Tracking volume (3-D readout wire drift chamber with 6180 cells) 3 Calorimeter volume (1940 plastic scintillator block) bkg ~ 0.3 c/y/kg [2.8-3.2] MeV  1 /2 0 (y) > 5.8  10 23 y (90% CL) m ee < 0.64 – 2.4 eV Present limit on 100 Mo 0 DBD  1 /2 0 (y) ~ 2  10 24 y m ee ~ 0.3 – 1.3 eV Expected sensitivity @ end 2009

23. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren23 Cuoricino Experiment Cuoricino Experiment Heat bath Thermal coupling Thermometer incident particle Crystal absorber  T = E/C Thermal signal Detector works at low temperature → 130 Te Q  = 2530 keV Detector: array of 62 5x5x5 cm 3 TeO 2 bolometers @ ~ 10 mKelvin Energy resolution: 0.28% @ Qvalue Location: LNGS (Italy) ~ 34% natural abundance

24. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren24 Cuoricino Experiment Cuoricino Experiment → 130 Te Q  = 2530 keV Detector: array of 62 5x5x5 cm 3 TeO 2 bolometers @ ~ 10 mKelvin Energy resolution: 0.28% @ Qvalue Location: LNGS (Italy) ~ 34% natural abundance

25. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren25 Cuoricino Experiment Cuoricino Experiment → 130 Te Q  = 2530 keV Detector: array of 62 5x5x5 cm 3 TeO 2 bolometers @ ~ 10 mKelvin Energy resolution: 0.28% @ Qvalue Location: LNGS (Italy) ~ 34% natural abundance bkg ~ 0.18 ± 0.01 c/keV/kg/y  1 /2 0 (y) > 3  10 24 y (90% CL) m ee < 0.2 – 0.98 eV Present limit on 130 Te 0 DBD  1 /2 0 (y) ~ 6.1  10 24 y m ee ~ 0.1 – 0.6 eV Expected sensitivity

26. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren26 Future (but not so far) experiments Future (but not so far) experiments

27. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren27 → 130 Te Q  = 2530 keV ~ 34% natural abundance CUORE (Cryogenic Underground Observatory CUORE (Cryogenic Underground Observatory for Rare Event) for Rare Event) CUORE (Cryogenic Underground Observatory CUORE (Cryogenic Underground Observatory for Rare Event) for Rare Event) 90 cm Expansion of Cuoricino 19 towers Cuoricino-like Detector: array of 988 5x5x5 cm 3 TeO 2 bolometers @ ~ 10 mKelvin (total mass = 741 kg) Energy resolution: 0.28% @ Qvalue Location: Hall A at LNGS (Italy)

28. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren28 CUORE (Cryogenic Underground Observatory CUORE (Cryogenic Underground Observatory for Rare Event) for Rare Event) CUORE (Cryogenic Underground Observatory CUORE (Cryogenic Underground Observatory for Rare Event) for Rare Event) F 0  = 9.2  10 25  ( T [ y ] ) 1/2 F 0  = 2.9  10 26  ( T [ y ] ) 1/2 5 y sensitivity (1  ) with conservative Assumption: b = 0.01 counts/(keV kg y) 5 y sensitivity (1  ) with aggressive assumption: b = 0.001 counts/(keV kg y)  M  < 20 – 100 meV  M  < 11 – 60 meV Montecarlo simulations of the background show that b = 0.001 counts / (keV kg y) is possible with the present bulk contamination of detector materials The problem is the surface background (alpha, beta energy-degraded) it must be reduced by a factor 10 – 100 with respect to Cuoricino work in progress! (only a factor 2 from the conservative assumption)  M  < 7 – 38 meV enriched CUORE

29. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren29 The GERDA Experiment The GERDA Experiment → 76 Ge Q  = 2039 keV Detector: Array of enriched (~86%) Ge Good energy resolution: < 0.19% at Q  Location: Hall A at LNGS (Italy), 3400 mwe the mountain provides a passive cosmic ray reduction

30. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren30 The GERDA Experiment: detector The GERDA Experiment: detector The detectors, arranged in strings, will be put in LAr in order to cool down them and also shield them.

31. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren31 The GERDA Experiment: setup The GERDA Experiment: setup Ge Array Germanium detectors Water / Muon-Veto (Č) Clean room / lock Steel-tank + Cu lining Liquid argon (nitrogen) - neutron moderator - Cerenkov medium for 4  muon veto Additional water shielding:

32. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren32 The GERDA Experiment The GERDA Experiment Tools for the bkg reduction: muon veto (Cerenkov detector) anticoincidence among the detectors pulse shape analysis segmented crystals active veto with LAr scintillation

33. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren33 GERDA goal and phases GERDA goal and phases Phase II: new segmented detectors exposure: 100 kg·y (it was 71 kg·y in HM) bkg: 10 -3 count/(keV kg y) Phase I: test claim 8 crystals from HM and IGEX (18 Kg) exposure: 15 kg·y bkg: 10 -2 cnt/(keV kg y) (exclude 99% c.l. or confirm 5  the 0nDBD claim) Bkg Goal: 10 -3 count/(keV kg y) improvement of a factor 100 with respect HM claim Further Possible Phase Collaboration with Majorana Experiment to construct a single larger experiment 37 Kg of enriched 76 Ge already bought for the construction of 2 nd phase detectors

34. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren34 SuperNEMO SuperNEMO Expansion of NEMO-3 → 82 Se Q  = 2995 keV Detector: tracking detector with different sources → 150 Nd Q  = 3367 keV Location: Modane (Fr) / Canfranc (SP) 5 m 1m Top view Tracking: drift chamber ~3000 cell (Gaiger mode) Calorimeter: scintillators + PM ~ 1000 if sc. blocks ~ 100 scint. bars

35. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren35 Improvement with respect to NEMO-3: SuperNEMO SuperNEMO NEMO-3 SuperNEMO 100 MoChoice of isotope 150 Nd or 82 Se 7 kg100 -200 kgIsotope Mass Efficiency8% 30% Internal contamination 208 Tl < 20 mBq/Kg 214 Bi < 300 mBq/Kg 208 Tl < 2 mBq/Kg 214 Bi < 10 mBq/Kg Energy resolution8% @ 3MeV4% @ 3MeV SENSITIVITY  1 /2 0 (y) ~ 2  10 24 y ~ 0.3 -1.3 eV  1 /2 0 (y) ~ 10 26 y ~ 50 meV Full experiment running at the end of 2012

36. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren36 EXO-200 (Enriched Xenon Observatory) EXO-200 (Enriched Xenon Observatory) → 136 Xe Q  = 2458 keV 200 kg of Xe enriched to 80% in 136 GOALS- search for 0nDBD with competitive sensitivity (and test the claim) - measure 2 DBD half life (best limit currently set by Bernabei et al. 1x10 22 y) - Understand the operation of a large LXe detector Understand bkg / characterize detectors materials Learn about large scale Xe enrichment Understand Xe handling, purification Detector: TPC of enriched liquid Xenon able to reconstruct the event position and topology. In this phase the Ba tagging technique (for the reduction of the background) will not be used

37. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren37 EXO-200 (Enriched Xenon Observatory) EXO-200 (Enriched Xenon Observatory) Improve energy resolution via simultaneous collection of ionized electrons and scintillation light

38. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren38 EXO-200 – the LXe TPC EXO-200 – the LXe TPC Teflon light reflector APD plane Central HV plane Supporting ring X and Y plane

39. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren39 EXO-200 (Enriched Xenon Observatory) EXO-200 (Enriched Xenon Observatory) In the first part of this year the cryostat has been commissioned and it has successfully liquefied 30 kg of natural Xenon Now they are moving all their structures from Stanford to WIPP

40. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren40 EXO-200 (Enriched Xenon Observatory) EXO-200 (Enriched Xenon Observatory) Low but finite radioactive background: 20 counts/year in ±2σ interval centered around the 2.458 MeV endpoint Negligible background from 2νDBD (T 1/2 > 1·10 22 yr R.Bernabei et al. measurement) No Ba tagging capability In case that the Klapdor’s claim is correct EXO-200 in 2 year will see: - 15 events on top of 40 events of bkg in the worst case (QRPA – upper limit) -> 2  - 162 events on top of 40 of bkg in the best case (NSM, lower limit) -> 11  Rodin et al Phys Rev C 68(2003)044302 Courier et al. Nucl Phys A 654 (1999) 973c

41. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren41 SNO++ SNO++ → 150 Nd Q  = 3368 keV Nd enriched to 56% in 150 Detector: refill SNO detector with liquid scintillator (linear alkylbenzene - LAB) loaded at 0.1% with enriched Nd (not enough light output in SNO+ if using 1% Nd loading) 560 kg of 150 Nd (compared to 37 g in NEMO-III) En resolution: 6.4% @ Qvalue Location: Sudbury (Canada)

42. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren42 Simulation: =150 meV 1 year of data a liquid scintillator detector has poor energy resolution; but enormous quantities of isotope (high statistics) and low backgrounds help compensate SNO++ SNO++ - Test on stability of Nd-LAB: no change in optical properties after > 1 year - Small Nd-LS detector with , source demonstrates it works as scintillator Sensitivity assumed background levels (U, Th) in the Nd-LS to be at the same level as KamLAND scintillator 2011: below 100 meV sensitivity reached if natural Nd and below 50 meVreached if enriched Nd

43. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren43 COBRA (CZT 0-neutrino Beta-decay Research Apparatus) COBRA (CZT 0-neutrino Beta-decay Research Apparatus) → 116 Cd Q  = 2809 keV Detector: 64000 1 cm 3 CZT detectors for a total mass of 418 kg → 183 kg of interesting isotope Enriched to 90% Location: LNGS (Italy)

44. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren44 COBRA (CZT 0-neutrino Beta-decay Research Apparatus) COBRA (CZT 0-neutrino Beta-decay Research Apparatus) The collaboration has mounted the first layer of a 4x4x4 1cm 3 new array (without enriched crystals) that is now running. They will complete the 64 detector array in autumn. Resulting Energy Resolution: 1.9% @ Qvalue Possibility to study the coincidence to make a Bkg reduction R&D on pixellisation of detector electrodes (200  m pixel) to make a particle ID for a Bkg reduction solid state TPC Reduction at least of a factor 10 of Bkg (10 c/(keV Kg y) 2x2x0.5 cm 3 with 64 pixels

45. Marisa Pedretti - INFNPhysics of Massive Neutrinos, Blaubeuren45 Future scenarios Future scenarios The future scenarios can be divided in possible steps: I step [100-500 meV]: to test of HM claim and to probe the QD region of neutrino mass SuperNEMO, CUORE, GERDA, EXO-200, SNO++ if the neutrino mass is in this range different experiment could see it with different isotopes. Precision measurement era for 0nDBD II step [15-50 meV]: to probe the IH region of neutrino mass. 1ton scale and 10 y SuperNEMO (especially with 150Nd), CUORE (especially if enriched), GERDA-III, SNO++ (enriched) discovery in 3-4 isotopes is necessary to confirm the observation III step [2-5 meV]: For this big leap in sensitivity new approaches are required. Next generation experiments are precious for the selection of the future approaches 100 tons of isotopes Unpredictable time scale and large investment in enrichment