1. 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,
Thanks to: G. Gratta, S., A. Giuliani, S. Schoenert,
T. Kishimito, M. Nomachi, K. Zuber, M. Chen, K. Inoue
F. Piquemal (CENBG) LP07

2. 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

3. 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)

4. 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,…..

5. 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: v1 [hep-ex]

6. 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

7. 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 ?

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

9. 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

10. (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)

11. 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

12. 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 Ca, 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)

13. Effective neutrino mass and q13
Isotope
mass
Required background level
~ 10 kg
100 – 1000 cts/yr/ton
~ 100 kg
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
This experimental review will be focused on the
last results of 10 kg and 100 kg experiments

14. 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

15. 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 > yr (90% CL)
T 1/2 > yr (90% CL)
<mn> < eV (90% CL)
<mn> < eV (90% CL)
Eur. Phys. J., A 12 (2001) 147
Phys. Rev. D65 (2002)

16. 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 > ans (90%)
<mn> <0.5 – 2.4 eV
bb(0n)
Energy (keV)
Stopped in 2008
DE/E ~ 8 keV at keV
Located in Gran Sasso Laboratory (Italy)
F. Piquemal (CENBG) LP07

17. Cuoricino results
Bolomètres: CUORICINO

18. CUORE

19. Array of 988 TeO2 5x5x5 cm3 crystals
CUORE
(Italy, USA,Spain)
750 kg of TeO2  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 > 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

20. 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: 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

21. 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

22. NEMO 3 Results

23. NEMO 3 Results

24. 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)
3MeV
3 MeV
T1/2(bb0n) > 2 x 1024 y
<mn> < 0.3 – 1.3 eV
T1/2(bb0n) > y
<mn> < 50 – 110 meV

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

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

27. 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

28. 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 > 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 > yr in 3 years of data <mn> < 0.1 eV

29. 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

30. Majorana
(USA, Russia, Japan)
Ge diodes
Very pure material
(Electroformed copper)
Segmentation
PSD improvement
R&D phase 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 > yr <mn> < eV (could confirm or refute Klapdor’s claim)
Collaboration with Gerda for 1 ton detector

31. EXO - 200 Liquid Xe TPC Ionization + scintillation
(USA, Canada, Switzerland, Russia)
Liquid Xe TPC
Ionization + scintillation
DE/E (FWHM)= 3.3
Possibility of Baryum ion tagging by
Laser florescence (136Xe  136Ba 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

32. 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) yr of data <mn> ~0.08 eV
500 kg of 150Nd 4yr <mn> ~ 0.03 eV
F. Piquemal (CENBG) LP07

33. KamLAND-Zen

34. 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 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

35. 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

36. 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

37. 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
< 109 – 135 (2yr)
GERDA
Diode Ge
76Ge
Gan sasso (Italy) 18 40
2012
0.01
0.001
< 250– 380
<
CUORE-0
CUORE
Bolometers
130Te 13
2013
0.12
<
<
<
SN module0
SuperNEMO
Tracko-calo
82Se, 150Nd
Modane (France) 7
100
2015
0.0001
1026
< 200 –600 (1yr)
< 53 – 140
SNO+
Liq. Scint.
150Nd
SNOLAB
(Canada) 44
< 100
KamLAND
Liq. Scinti
Kamioka
(Japan)
400
< ~ 60 (2 yr)

38. 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

39. 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 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

40. 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

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

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