Double Beta Decay review Fabrice Piquemal Laboratoire Souterrain de Modane (CNRS/IN2P3-CEA/DSM) and CENBG, University Bordeaux 1 CNRS/IN2P3 Thanks to: G. Gratta, S., A. Giuliani, S. Schoe T. Kishimito, M. Nomachi, K. Zuber, M. Chen, K. NNN 2010, Toyama Dec,14-16 2010
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 , - PowerPoint PPT Presentation
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Double Beta Decay review
Fabrice PiquemalLaboratoire Souterrain de Modane (CNRS/IN2P3-CEA/DSM)
and CENBG, University Bordeaux 1 CNRS/IN2P3
Thanks to: G. Gratta, S., A. Giuliani, S. Schoenert, T. Kishimito, M. Nomachi, K. Zuber, M. Chen, K. Inoue
NNN 2010, Toyama Dec,14-16 2010
- 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 decay: physics case
- Leptonic number violation
(A,Z) (A,Z+2) + 2e-
Double Beta decays
2nd order process of weak interactionAlready observed for several nuclei
Single beta decay forbidden (energy)
or strongly suppressed by large angular
momentum change
Decay to ground state or excited states
bb
e-e-
nn
bb(2n) bb(0n) e-
e-
DL =2
bb(0n) Majorana neutrino (n=n)
(V+A) current <mn>,<l>,<h>
(A,Z) (A,Z+2) + 2 e-
Process parameters
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
Light neutrino exchange <mn>
Majoron emission <gM>SUSY l’111,l’113l’131,…..
Neutrinoless Double Beta decay
Discovery implies DL=2 and Majorana neutrino
bb(0n) observables
Electron energy sum
150Nd distribution s arxiv: 1005.1241v1 [hep-ex]
Angular distribution
Massmechanism
MassmechanismRHC
Ee1 – Ee2 distribution
RHC
bb(2n) bb(0n)
From G. Gratta
Experiments Isotopes Techniques Main caracteristics
NEMO3 100Mo,82Se Tracking + calorimeter Bckg rejection, isotope choiceSuperNEMO 82Se, 150Nd Tracking + calorimeter Bckg rejection, isotope choiceCuoricino 130Te Bolometers Energy resolution, efficiencyCUORE 130Te Bolometers Energy resolution, efficiencyGERDA 76Ge Ge diodes Energy resolution, eficiencyMajorana 76Ge Ge diodes Energy resolution, efficiencyCOBRA 130Te, 116Cd ZnCdTe semi-conductors Energy resolution, efficiencyEXO 136Xe TPC ionisation + scintillation Mass, efficiency, final state signatureMOON 100Mo Tracking + calorimeter Compactness, Bckg rejectionCANDLES 48Ca CaF2 scintillating crystals Efficiency, Background
arXiv:1008.5260v2 : Tomás R. Rodríguez, G. Martinez-Pinedo
Nuclear Matrix Element
Qbb MeV2 3 4
76Ge 130Te76Xe100Mo 82Se
5
150Nd 96Zr
48Ca
Background components
+ bb(2n) for tracko-calo or calorimeter with modest energy resolution
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
+ for pure calorimeter Surface or bulk contamination in a emitters, cosmogenic production
2.614 MeVHighest gamma-ray from natural radioactivity
T n0
2/1 e
A
M . t
NBckg . DE(y)
<mn > M1/4
CalorimeterSemi-conductors
BolometersSource = detector
e, DE
b
b
b
b
Calorimeter(Loaded) Scintillator
Source = detector
e, M
Tracko-caloSource detector
NBckg, isotope choice
Xe TPCSource = detector
b
b
e,M, (NBckg)
b
b
M: masse (g)e : efficiencyKC.L.: Confidence levelN: Avogadro number
t: time (y)NBckg: Background events (keV-1.g-1.y-1)DE: energy resolution (keV)
Experimental sensitivity
Calorimeter vs Tracko-calo
bb(0n) bb(0n)
bb(0n) bb(0n)
Calorimeter Tracko-calo
High energy resolutionModest background rejection
High background rejectionModest energy resolution
keV
keV
MeV
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)
Why so many experiments or projects ?
Effective neutrino mass and q13
100 – 1000 cts/yr/ton
1 – 10 cts/yr/ton
0.1 – 1 cts/yr/ton
Isotopemass
~ 10 kg 2011
~ 1000 kg
Required background level
Heidelberg-Moscow (2001) ~11 kg of enriched Ge
bb(0n) ?
|mee
|
S T Petcov 2009 J. Phys.: Conf. Ser. 173 012025
~ 100 kg 2015
This experimental review will be focused on the last results of 10 kg and 100 kg experiments
SNO++ (150Nd)
EXO (136Xe)Majorana (76Ge)
Cuoricino/CUORE (130Te)GERDA (76Ge)COBRA (116Cd)
CANDLES (48Ca)KamLAND-ZEN (136Xe)MOON (100Mo)
bb(0n) : experiments and projects
CalorimeterSource = detector
b
b
b
b
Tracko-caloSource detector
EXO gaz (136Xe)
DCBA (150Nd)
NEMO3/SuperNEMO (82Se, 150Nd, 48Ca)NEXT (136Xe)
<mn> <0.35-1.05 eV (90% CL)
T 1/2 >1.9 1025 yr (90% CL)
Eur. Phys. J., A 12 (2001) 147
35.5 k.yr
0.06 cts/keV/kg/yr
Heidelberg-Moscow (2001) ~11 kg of enriched 76Ge (86%)
8.9 kg.yr without PSA4.6 kg.y with PSA
Phys. Rev. D65 (2002) 092007
IGEX (2002)~ 8.4 kg of enriched 76Ge (86%)
T 1/2 >1.57 1025 yr (90% CL)
<mn> <0.33-1.31 eV (90% CL)
bb(0n): Present situation
Ge diode detectors
Bolomètres: CUORICINOCuoricino
Heat sink
ThermometerDouble beta decay
Crystal absorber
Bolometers of TeO2
DE/E ~ 8 keV at 2 527 keV
Located in Gran Sasso Laboratory (Italy)
Stopped in 2008
Bolomètres: CUORICINOCuoricino results
CUORE
750 kg of TeO2 203 kg of 130Te
Array of 988 TeO2 5x5x5 cm3 crystals
Improvement of surface event rejection
Data taking foreseen in 2013
Nbckg=0.01 cts.keV-1.kg-1.yr-1
T½ > 2.1 1026 yr
<mn> < 0.03 – 0.17 eV
Goal :Nbckg=0.01 cts.keV-1.kg-1.yr-1
Expected sensitivity
(Italy, USA,Spain)
(Factor 20 compared to Cuoricino)
LUCIFER:R&D on scintillating bolometers like 82Se 116CdWO4
CUORE
Test of 1 tower of CUORE in Cuoricino in 2011
Vertex
bb events
E1+E2= 2088 keV Dt= 0.22 ns(Dvertex) = 2.1 mm
E1
E2
e-
e-
NEMO 3Tracko-calo detectorDrift chamber (6000 cells)Plastic scintillator + PMT (2000)10 kg of isotopesDE/E (FWHM) : 8 % @ 3 MeVLocated in Modane Underground Lab (France)
Bckg: 0.025 cts/keV/kg/yr
Bckg
bb sources (thickness 0 mg/cm2)
82Se (0,93 kg)
bb(2n)
Multi-source detector
NEMO 3 Results100Mo, 23.4 kg.yr 620 000 events
Bosonic fraction of neutrino wave functionSin c < 0.6
NEMO 3 Results
NEMO 3 Results
7 kg 100 kg isotope mass M
15 % ~ 30 %
isotope 100Mo
82Se ,150Nd or 48Ca
T1/2 (bb0n) > ln 2 M e Tobs N90
NA
A
NEMO-3 SuperNEMO
internal contaminations 208Tl and 214Bi in the bb foil
SuperNEMO phase I : 2011 – 2014Contruction demontrator module with 7 kg of 82Se (1 kg of 48Ca ?)Commissing @LSM 2013Sensitivity in 1 year: T1/2 < 5 1024 y <mn> < 0.2 – 0.6 eV
SuperNEMO phase II : 2014 – 2019100 kg of 82Se (or 150Nd,or 48Ca)T1/2 > 1026 y <mn> < 0.05 – 0.14 eV
Ge detector improvementsStrategies: Ge detectors in liquid nitrogen to remove materials Active shielding and segmentation of detectors to reject gamma-rays
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
Very pure material(Electroformed copper)
SegmentationPSD improvement
R&D phase 30-60 kg of 86% enriched 76Ge crystals
Some of the crystals segmented
T1/2 > 1. 1026 yr <mn> < 0.14 eV (could confirm or refute Klapdor’s claim)