Double Beta Decay review Fabrice Piquemal Laboratoire Souterrain de Modane (CNRS/IN2P3-CEA/DSM) and CENBG, University Bordeaux 1 CNRS/IN2P3 NNN 2010, Toyama Dec,14-16 2010 Thanks to: G. Gratta, S., A. Giuliani, S. Schoenert, T. Kishimito, M. Nomachi, K. Zuber, M. Chen, K. Inoue F. Piquemal (CENBG) LP07

Double Beta decay: physics case (A,Z)  (A,Z+2) + 2e- - Leptonic number violation - Nature of neutrino : Dirac (n n) or Majorana (n =n) - Absolute neutrino mass and neutrino mass hierarchy Right-handed current interaction CP violation in leptonic sector Search of Supersymmetry and new particles

Double Beta decays bb bb(0n) bb(2n) bb(0n)  Majorana neutrino (n=n) Single beta decay forbidden (energy) or strongly suppressed by large angular momentum change Decay to ground state or excited states bb bb(0n) bb(2n) e- e- e- e- n n DL =2 2nd order process of weak interaction Already observed for several nuclei bb(0n)  Majorana neutrino (n=n)

Neutrinoless Double Beta decay (A,Z) (A,Z+2) + 2 e- Discovery implies DL=2 and Majorana neutrino T1/2= F(Qbb,Z) |M|2 <mn>2 -1 Phase space factor Nuclear matrix element Effective mass: <mn>= m1|Ue1|2 + m2|Ue2|2.eia1 + m3|Ue3|2.eia2 |Uei|: mixing matrix element a1 et a2: Majorana phase 5 Process parameters Light neutrino exchange <mn> (V+A) current <mn>,<l>,<h> Majoron emission <gM> SUSY l’111,l’113l’131,…..

bb(0n) observables Electron energy sum bb(0n) bb(2n) From G. Gratta Angular distribution Mass mechanism RHC Ee1 – Ee2 distribution 150Nd distribution s arxiv: 1005.1241v1 [hep-ex]

Why so many experiments or projects ? Isotopes Techniques Main caracteristics NEMO3 100Mo,82Se Tracking + calorimeter Bckg rejection, isotope choice SuperNEMO 82Se, 150Nd Cuoricino 130Te Bolometers Energy resolution, efficiency CUORE GERDA 76Ge Ge diodes Energy resolution, eficiency Majorana COBRA 130Te, 116Cd ZnCdTe semi-conductors EXO 136Xe TPC ionisation + scintillation Mass, efficiency, final state signature MOON 100Mo Compactness, Bckg rejection CANDLES 48Ca CaF2 scintillating crystals Efficiency, Background SNO++ 150Nd Nd loaded liquid scintillator Mass, efficiency XMASS Liquid Xe CARVEL CaWO4 scintillating crystals Yangyang 124Sn Sn loaded liquid scintillator DCBA Gazeous TPC Bckg rejection, efficiency

Abondance isotopique (%) Double beta decay isotopes Isotope Q (MeV) Abondance isotopique (%) G0(an-1) x 1025 Enrichment method 48Ca 4.271 0.187 2.44 Laser ? 76Ge 2.040 7.8 0.24 Centrifugation 82Se 2.995 9.2 1.08 96Zr 3.350 2.8 2.24 100Mo 3.034 9.6 1.75 116Cd 2.802 7.5 1.89 130Te 2.528 33.8 1.70 136Xe 2.479 8.9 1.81 150Nd 3.367 5.6 8.00 Centrifugation ?

Nuclear Matrix Element arXiv:1008.5260v2 : Tomás R. Rodríguez, G. Martinez-Pinedo

Background components 2.614 MeV Highest gamma-ray from natural radioactivity 100Mo 82Se 150Nd 96Zr 48Ca 76Ge 76Xe 130Te 2 3 4 5 Qbb MeV Natural radioactivity (40K, 60Co,234mPa, external 214Bi and 208Tl…) 214Bi and Radon, 208Tl (2.6 MeV g line) and Thoron, g from (n,g) reaction and muons bremstrahlung + bb(2n) for tracko-calo or calorimeter with modest energy resolution + for pure calorimeter Surface or bulk contamination in a emitters, cosmogenic production

(Loaded) Scintillator Experimental sensitivity M . t e A (y)  NBckg . DE <mn >  M1/4 M: masse (g) e : efficiency KC.L.: Confidence level N: Avogadro number t: time (y) NBckg: Background events (keV-1.g-1.y-1) DE: energy resolution (keV) Calorimeter Semi-conductors Bolometers Source = detector Calorimeter (Loaded) Scintillator Source = detector Tracko-calo Source  detector Xe TPC Source = detector b b b b b b b b e, DE e, M NBckg, isotope choice e,M, (NBckg)

Calorimeter vs Tracko-calo High energy resolution Modest background rejection High background rejection Modest energy resolution bb(0n) bb(0n) keV bb(0n) bb(0n) keV MeV

Why so many experiments or projects ? What is the most favorable isotope and the best technique ? Phase space factor: 48Ca, 150Nd, 96Zr Nuclear matrix element  not yet reliable predictions Backgrounds > 2,6 MeV 48Ca, 150Nd, 96Zr, 100Mo, 82Se, 116Cd > 3.2 MeV (radon) 48Ca, 150Nd, 96Zr Enrichment: 130Te (Natural isotopic abundance 34%) 136Xe (gaz, easy to enrich) Best techniques : Bolometers, Ge diodes: energy resolution 130Te (82Se, 116Cd), 76Ge Tracko-calo : background rejection 82Se, (48Ca, 150Nd) TPC Xe: background rejection if tagging of Ba 136Xe Large liquid scintillator: mass of isotopes 136Xe, 150Nd A problem to understand: the background at ~100 kg (related to istopes and techniques)

Effective neutrino mass and q13 Isotope mass Required background level ~ 10 kg 2011 100 – 1000 cts/yr/ton ~ 100 kg 2015 1 – 10 cts/yr/ton ~ 1000 kg 0.1 – 1 cts/yr/ton |mee| Heidelberg-Moscow (2001) ~11 kg of enriched Ge bb(0n) ? S T Petcov 2009 J. Phys.: Conf. Ser. 173 012025 This experimental review will be focused on the last results of 10 kg and 100 kg experiments

bb(0n) : experiments and projects NEMO3/SuperNEMO (82Se, 150Nd, 48Ca) NEXT (136Xe) SNO++ (150Nd) DCBA (150Nd) EXO (136Xe) Majorana (76Ge) EXO gaz (136Xe) Cuoricino/CUORE (130Te) GERDA (76Ge) COBRA (116Cd) CANDLES (48Ca) KamLAND-ZEN (136Xe) MOON (100Mo) Tracko-calo Source  detector Calorimeter Source = detector b b b b

bb(0n): Present situation Ge diode detectors Heidelberg-Moscow (2001) ~11 kg of enriched 76Ge (86%) IGEX (2002) ~ 8.4 kg of enriched 76Ge (86%) 35.5 k.yr 8.9 kg.yr without PSA 4.6 kg.y with PSA 0.06 cts/keV/kg/yr T 1/2 >1.9 1025 yr (90% CL) T 1/2 >1.57 1025 yr (90% CL) <mn> <0.35-1.05 eV (90% CL) <mn> <0.33-1.31 eV (90% CL) Eur. Phys. J., A 12 (2001) 147 Phys. Rev. D65 (2002) 092007

Cuoricino Bolometers of TeO2 Bolomètres: CUORICINO Thermometer Heat sink Thermometer Double beta decay Crystal absorber 214Bi (238U chain) 208Tl (232Th chain) 60Co pile up 5.3 kg.an T1/2 > 1. 1024 ans (90%) <mn> <0.5 – 2.4 eV bb(0n) Energy (keV) Stopped in 2008 DE/E ~ 8 keV at 2 527 keV Located in Gran Sasso Laboratory (Italy) F. Piquemal (CENBG) LP07

Cuoricino results Bolomètres: CUORICINO

CUORE

Array of 988 TeO2 5x5x5 cm3 crystals CUORE (Italy, USA,Spain) 750 kg of TeO2  203 kg of 130Te Array of 988 TeO2 5x5x5 cm3 crystals Improvement of surface event rejection Goal :Nbckg=0.01 cts.keV-1.kg-1.yr-1 (Factor 20 compared to Cuoricino) LUCIFER: R&D on scintillating bolometers like 82Se 116CdWO4 Expected sensitivity Nbckg=0.01 cts.keV-1.kg-1.yr-1 T½ > 2.1 1026 yr <mn> < 0.03 – 0.17 eV Test of 1 tower of CUORE in Cuoricino in 2011 Data taking foreseen in 2013 F. Piquemal (CENBG) LP07

NEMO 3 Tracko-calo detector bb events Bckg: 0.025 cts/keV/kg/yr e- e- Drift chamber (6000 cells) Plastic scintillator + PMT (2000) 10 kg of isotopes DE/E (FWHM) : 8 % @ 3 MeV Located in Modane Underground Lab (France) Bckg: 0.025 cts/keV/kg/yr Bckg sourcesthicknessmg/cm2) 82Se (0,93 kg)  Multi-source detector E1 e- Vertex e- E1+E2= 2088 keV t= 0.22 ns (vertex) = 2.1 mm E2 bb events F. Piquemal (CENBG) LP07

NEMO 3 Results 100Mo, 23.4 kg.yr 620 000 events Bosonic fraction of neutrino wave function Sin c < 0.6 F. Piquemal (CENBG) LP07

NEMO 3 Results

NEMO 3 Results

internal contaminations energy resolution (FWHM) From NEMO 3 to SuperNEMO NA M  e  Tobs T1/2 (bb0n) > ln 2   A N90 NEMO-3 SuperNEMO isotope 100Mo 82Se ,150Nd or 48Ca 7 kg 100 kg isotope mass M 15 % efficiency  ~ 30 % internal contaminations 208Tl and 214Bi in the bb foil 208Tl: < 20 mBq/kg 214Bi: < 300 mBq/kg 208Tl < mBq/kg if 82Se: 214Bi < 10 mBq/kg energy resolution (FWHM) 8% @ 3MeV 4% @ 3 MeV T1/2(bb0n) > 2 x 1024 y <mn> < 0.3 – 1.3 eV T1/2(bb0n) > 1026 y <mn> < 50 – 110 meV

SuperNEMO conceptual design 20 modules for 100 kg Source (40 mg/cm2) 12m2 Tracking (~2-3000 Geiger cells). Calorimeter (500 channels) Total:~ 40 000 – 60 000 geiger cells channels ~ 10 000 PMT 5 m 1 m Top view 25

SuperNEMO SuperNEMO phase I : 2011 – 2014 DE/E < 4% (FWHM) @ Qbb demonstrated (< 8% @ 1 MeV) Commissioning of wiring robot FWHM = 7,1 % (7,6% before energy loss correction) SuperNEMO phase I : 2011 – 2014 Contruction demontrator module with 7 kg of 82Se (1 kg of 48Ca ?) Commissing @LSM 2013 Sensitivity in 1 year: T1/2 < 5 1024 y <mn> < 0.2 – 0.6 eV SuperNEMO phase II : 2014 – 2019 100 kg of 82Se (or 150Nd,or 48Ca) T1/2 > 1026 y <mn> < 0.05 – 0.14 eV SuperNEMO @ LSM extension

Ge detector improvements Strategies: Ge detectors in liquid nitrogen to remove materials Active shielding and segmentation of detectors to reject gamma-rays e-  detector segments Liquid argon scintillation crystal anti-coincidence Detector segmentation pulse shape analysis R&D: liquid argon anti-coincidence

GERDA Removal of matter Use of liquid nitrogen or argon for active shielding Segmented detectors in futur Improvement of Pulse Shape Analysis PHASE I: 17.9 kg of enriched 76Ge (from HM and IGEX) In 1 year of data if B=10-2 cts/keV/kg/yr (check of Klapdor’s claim) Start 2011 at Gran Sasso T1/2 > 3 1025 yr <mn> < 0.25 eV PHASE II: 40 kg of enriched 76Ge (20 kg segmented) 2012 if B=10-3 cts/keV/kg/an T1/2 > 2 1026 yr in 3 years of data <mn> < 0.1 eV

GERDA Nov/Dec.’09: Liquid argon fill Jan ’10: Commissioning of cryogenic system Apr/Mai ’10: emergency drainage tests of water tank Apr/Mai ’10: Installation c-lock May ’10: 1st deployment of FE&detector mock-up June ‘10: Commissioning with natGe detector string Soon: start Phase I physics data taking

Majorana (USA, Russia, Japan) Ge diodes Very pure material (Electroformed copper) Segmentation PSD improvement R&D phase 30-60 kg of 86% enriched 76Ge crystals Some of the crystals segmented Bckg goal ~ 1 count/ROI/t-yr (after analysis cuts) 30 kg of enriched Ge, running 3 yr. Data taking scheduled for 2011 T1/2 > 1. 1026 yr <mn> < 0.14 eV (could confirm or refute Klapdor’s claim) Collaboration with Gerda for 1 ton detector

EXO - 200 Liquid Xe TPC Ionization + scintillation (USA, Canada, Switzerland, Russia) Liquid Xe TPC Ionization + scintillation DE/E (FWHM)= 3.3 % @Qbb Possibility of Baryum ion tagging by Laser florescence (136Xe  136Ba++ + 2 e R&D in progress Gazeous TPC R&D 200 kg of 136Xe, no Ba ion tagging Installation in WIPP underground lab Possibility to measure bb(2n) EXO-200 full of natural Xe - Tuning on all systems - Engineering runs - Physics mode as soon as possible

SNO++ Scintillator loaded with Nd. Test of light attenuation 500 kg of 150Nd 1 year <mn> = 150 meV only internal Th and 8B solar neutrino backgrounds are important Test of light attenuation Study of Nd purification (factor 1000 per pass in Th and Ra) 56 kg of 150Nd (0,1 % of natural Nd) 4 yr of data <mn> ~0.08 eV 500 kg of 150Nd 4yr <mn> ~ 0.03 eV F. Piquemal (CENBG) LP07

KamLAND-Zen

CANDLES Pure CaF2 crystals CANDLES III (Japan) Pure CaF2 crystals Wave length shifter in LS PSD to reject g and a CaF2(Pure) Liquid Scintillator (Veto Counter) Buffer Oil Large PMT CANDLES III 103 cm3 × 96 crystals  305 kg Data taking in 2011 @ Kamioka Expected BG: 0.14 event/yr (30 µBq/kg) <mn> ~0.5 eV CANDLES IV : 3 tons of CaF2 (3 mBq/kg) 6 yr <mn> ~0.1 eV

DCBA Drift Chamber beta-ray Analyser Prototype with 207Bi : 10% (FWHM) energy resolution X position s= 0.5 mm Y position s= 0.02 mm X position s= 6 mm

COBRA 4x4x4 detector array = 0.42 kg CdZnTe Installed at LNGS (UK, Germany, Italy, poland, Slovaquia, Finland, USA) Array of 1cm3 CdZnTe detectors Cd-113 beta decay with half-life of about 1016 yrs 4x4x4 detector array = 0.42 kg CdZnTe Installed at LNGS Test of coincidence rejection Measure of 113Cd F. Piquemal (CENBG) LP07

Sensitivities 2013 - 2018 Technique Location Mass kg start Bckg Cts/keV/kg/yr T1/2(0n) <mee> meV EXO Liquid Xe 136Xe WIPP (USA) 200 2011 0.002 6.4 1025 < 109 – 135 (2yr) GERDA Diode Ge 76Ge Gan sasso (Italy) 18 40 2012 0.01 0.001 3. 1025 3. 1026 < 250– 380 < 80 - 120 CUORE-0 CUORE Bolometers 130Te 13 2013 0.12 8. 1025 2.1 1026 6.5 1026 <100 - 200 < 41 -82 < 23- 47 SN module0 SuperNEMO Tracko-calo 82Se, 150Nd Modane (France) 7 100 2015 0.0001 6. 1024 1026 < 200 –600 (1yr) < 53 – 140 SNO+ Liq. Scint. 150Nd SNOLAB (Canada) 44 < 100 KamLAND Liq. Scinti Kamioka (Japan) 400 < ~ 60 (2 yr)

Summary Present 10 kg experiment reach a sensitivity <mn> < 0.3 – 1 eV Background ~100 – 1000 cts/ton/yr 1OO kg experiments will reach a sensitivity on <mn> < ~50 meV in the next 5 yr Background ~ 1 – 10 cts/ton/yr (Remark: to win a factor 10 on bckg it takes 5 – 10 yrs) Step by step approach: GERDA, MAJORANA, CUORE, SuperNEMO Agressive approach (no 10 kg prototype): EXO, SNO++, KamLAN-Zen, NEXT Possibility to enrich 150Nd, 96Zr or 48Ca in the futur ? 100 kg experiments essential to validate technique and background for 1 ton experiments

100 kg experiments Step by step approach GERDA Ge diode in LAr CUORE 130Te bolometers Gran Sasso laboratory Gran Sasso laboratory 2010: 18 kg of 76Ge (HM and IGEX crystals) 1st results 2011 2012: 40 kg of 76Ge CUORE-0 39 kg of natTe 13 kg of 130Te Data taking 2011 CUORE 200 kg Data taking 2013 (scintillating bolometres ?) + Energy resolution + Natural Te + Energy resolution SuperNEMO tracko-calo MAJORANA Ge segmented Diode Modane laboratory DUSEL laboratory Module-0 7 kg of 82Se (150Nd) Data taking 2013 20 Module 100 kg Data taking 2015 2011: 20 kg of natGe 2013 ? : 30 kg of 76Ge + Background rejection + Multi-isotopes + Energy resolution

100 kg experiments Agressive approach (no 10 kg prototype) EXO liquid Xenon SNO++ Nd salt + liquid scintillator WIPPL laboratory SNOLAB laboratory 2010: 200 kg of 136Xe Results 2013 Ba tagging R&D 2010: 740 kg of natNd (44 kg of 150Nd) Dissolved in scintillator + Large mass + Possibility to tag daughter nucleus + Large mass + low background detector NEXT Xe high pressure TPC KamLAND-Zen Xe + liq. scintillator Canfranc laboratory Kamioka laboratory 2011: 1 kg of 136Xe 2013 : 100 kg 2011: 400 kg of 136Xe Dissolved in liq. scintillator + Large mass + Background rejection

bb(0n) signal ? HM claim T1/2 = (0.69 – 4.18) 1025 2006: Improvement of PSA (6s) 2004 (4s) +0.44 T1/2 = 2.23 1025 yr T1/2 = (0.69 – 4.18) 1025 <mn> = 0.28-0.58 (90%) -0.31 <mn> = 0.32 ± 0.03 eV

Nuclear Matrix Element From F. Simkovic (neutrino 2010) arXiv:1008.5260v2 : Tomás R. Rodríguez, G. Martinez-Pinedo