[PPT] - Search for Majorana neutrinos and double beta decay experiments PowerPoint Presentation

SLIDE 1

Search for Majorana neutrinos and double beta decay experiments

Xavier Sarazin Laboratoire de l’Accélérateur Linéaire (CNRS-IN2P3, Univ. Paris-Sud 11)

SLIDE 2

Only two n states:

|nL, h= -1/2 > CPT |nR, h= +1/2 >

Neutrino is the only fermion with Q = 0  Neutrino might be a Majorana particle n = n ? Massive Majorana n  Violation of the Leptonic Number

Leptogenesis in the Early Universe through the Majorana neutrino
See-saw mechanism to explain the small mass of the neutrino

Observation of bb0n decay is the most sensitive way to probe Majorana

Majorana Neutrino

SLIDE 3

For few isotopes, b-decay is forbiden bb2n process (second order b-decay)

bb2n and bb0n decay

Energy Sum of the two electrons Qbb

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For few isotopes, b-decay is forbiden bb2n process (second order b-decay)

bb2n and bb0n decay

Energy Sum of the two electrons

If neutrino is a Majorana particle  bb0n Process bb0n

Process L = 2

Majorana neutrino exchange

mn

Right Handed weak current

V+A

Majoron production
Exchange of SUSY particles

Qbb

Energy and angular distributions will be different !

SLIDE 5

 

2 2 1 2 / 1 ee

m M T

n n n

 =

Theoretical predictions

Phase space factor Nuclear Matrix Element  Theoretical uncertainty Effective mass Constraint by n oscillations



=

i ei ee

i

m U m

n 2

In the case of an standard exchange of a Majorana neutrino

SLIDE 6

Merle & Rodejohann PRD 73, 073012 (2006)

Constraints from neutrino oscillations

In the case of an standard exchange of a Majorana neutrino

Degenerate masses

meV 50

2 3 2 1

  >   

atm

m m m m m

n

meV 50 mν >

Normal hierarchy ?

mν

Inverted hierarchy

meV 50 m 10

ν 



SLIDE 7

Nuclear Matrix Elements

Calculated T1/2(bb0n) to start exploring the Inverted Hierarchy in the case of exchange of Majorana neutrino mn  50 meV

from Duek et al. , Phys. Rev. D 83 (2011)

QRPA Tüe. Simkovic, Phys. Rev. C 79

(2009); Fang, Phys. Rev. C 82 (2010)

QRPA Jy. Kortelainen, Phys. Rev. C 75

and C 76 (2007)

NSM Shell Model Menendez, Nucl.
Phys. A818 (2009); Phys. Rev. C 80 (2009)
IBM Interacting Boson Model

Barea, Phys. Rev. C79 (2009)

GCM Generating Coordinate Method

Rodriguez, Phys. Rev. Lett. 105 (2010)

PHFB

Projected Hartree-Fock- Bogoliubov Rath, Phys. Rev. C 82 (2010)

~ 3 1025 ~ 3 1027 Nnuclei (76Ge) ≈ 10×Nnuclei (100Mo, 150Nd)

SLIDE 8

   

bs

excl avog

T bkg N M A N T 2 ln

2 / 1

 n bb >

Sensitivity

M Large Mass of enriched bb isotopes
  High efficiency
Nexcl  Low background
High energy resolution

SLIDE 9

Cosmic rays and induced g’s  underground lab
High energy g’s up to ~ 10 MeV produced by neutron captures
Natural radioactivity (238U and 232Th chain):

 208Tl, 214Bi, Radon (222Rn) and Thoron (220Rn), a-decay (in case of no e-/a discrimination)

208Tl: Qb= 2.4 MeV + g 2.6 MeV 214Bi: Qb = 3.2 MeV

 Ultra low radioactive detectors: Detector materials: A(208Tl) < 1 mBq/kg Source A(208Tl) < 1-10 mBq/kg For comparison, a standard Al foil: A(208Tl) ~ 100 mBq/kg

Origin of background

SLIDE 10

Current best limits obtained in bb0n search

mn limit (eV)

Limits at 90% C.L.

Inverted hierarchy

GERDA NEMO-3 Cuoricino Kamland-Zen EXO-200

T1/2(0n) limit (1024 yrs)

1024 yrs 1 ev

SLIDE 11

Calorimeters

Ge diodes Ionisation Bolometers Phonon + Scint. Scintillators Scintillations

Liq. Xe TPC

Ionisation+scint. Gerda (76Ge) Majorana (76Ge) Cuore (130Te) Lumineu (100Mo) Lucifer (82Se) Amore (100Mo) Kamland-Zen (136Xe) SNO+ (130Te) Candles-3 (48Ca) EXO (136Xe) Tracko-Calo SuperNEMO

(76Se, 150Nd, 48Ca)

Gas Xe TPC Ionisation NEXT

(136Xe)

Pixel. CdZnTe

Ionisation Cobra

(116Cd)

Electron Tracking

SLIDE 12

Ge diodes

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GERDA (LNGS)

76Ge

(Qbb = 2040 keV)

“Bare” Ge crystals in Liquid Argon
Liq. Argon = cryostat + shield
Ext. Water tank for shield + m-veto
Detector arrays  gradual deployment

SLIDE 14

GERDA (LNGS)

“Bare” Ge crystals in Liquid Argon
Liq. Argon = cryostat + shield
Ext. Water tank for shield + m-veto
Detector arrays  gradual deployment

76Ge

(Qbb = 2040 keV)

Phase 1 (2011-2013) ~ 18 kg 76Ge

8 old 76Ge detectors (HdM, IGEX) 5 new BEGe detectors FWHM ~ 3 keV @ 2.6 MeV for BEGe Energy peaks stable within  1 keV 21.6 kg.yr 76Ge exposure Bkg ~ 10-2 cts/keV/kg/yr  This is 10 times lower than previous Ge experiments !  T1/2(bb0n) > 2.1 1025 yr (90% C.L.)

Without PSA With PSA

Mod. Phys. Lett. A 29, 1430001 (2014)

SLIDE 15

GERDA (LNGS)

“Bare” Ge crystals in Liquid Argon
Liq. Argon = cryostat + shield
Ext. Water tank for shield + m-veto
Detector arrays  gradual deployment

76Ge

(Qbb = 2040 keV)

Phase 2 (2014) ~ 50 kg 76Ge

30 new Broad Energy (BEGe) detectors  High pulse shape discrimination performances Single Site (bb0n) / Multi Sites (g bkg) discrimination  Detection of Ar scintillation light Liquid Argon as active shield with the scintillation veto Target : Bkg ~ 10-3 cts/keV/kg/yr  T1/2(bb0n) > 2 1026 yr in 5 yrs of data

SLIDE 16

MAJORANA

76Ge

(Qbb = 2040 keV) Under construction in Sanford Underground Laboratory (USA) Up to 40 kg of HBGe crystals Standard shield with electroformed Copper and lead Start data with first cryostat end 2014 LOI between GERDA & MAJORANA Collaborations Intention to merge for O(1 ton) exp. selecting the best technologies

SLIDE 17

Bolometers

SLIDE 18

T1/2(bb0n) > 2.8 1024 y (90%C.L.) CUORICINO (2003 – 2008) 40 kg natTe02  ~ 10 kg 130Te BKG = 0.17 cts/(keV.kg.yr) ~ 70% a’s from crystals and Cu surfaces ~ 30% external 2.6 MeV g-ray (208Tl) from cryostat Qbb(130Te) ~ 2530 keV ~50 crystals natTeO2 FWHM ~ 6 keV @ Qbb

60Co

natTe02 crystal CUORICINO (LNGS, Italy)

Astropart. Phys. 34, 822 (2011)

SLIDE 19

CUORE (start 2015) 19 Cuoricino-like towers in a new cryostat 740 kg natTe02  200 kg 130Te Sensitivity expected in 5 years T1/2(bb0n) > 1026 y Target: Bkg = 0.01 cts/(keV.kg.yr) (17 times lower than Cuoricino) CUORE-0 = 1st CUORE tower running in the cuoricino cryostat Preliminary result of the background measurement

a bkg reduced by a factor 6
g bkg still dominated by cuoricino cryostat: we must wait for the new cuore cryostat

natTe02 crystal CUORE (LNGS, Italy)

SLIDE 20

Expected CUORE bkg = 0.01 cts/(keV.kg.yr)  ~ 35 cts/year in the bb0n energy window (fwhm)  This is still a high level of bkg !  CUORE bkg must be reduced by an extra factor 10 at least ! The way to reach a « zero bkg » with bolometers:

Rejection 2.6 MeV g-ray bkg  use crystal with Qbb > 2.6 MeV
ZnMoO4, CaMoO4 (100Mo, Qbb= 3 MeV)
ZnSe (82Se, Qbb= 3 MeV)
CdWO4 (116Cd, Qbb= 2.8 MeV)
Rejection a bkg  Scintillating bolometers for a / (e-,g) discrimination
S. Pirro et al. Physics of Atomic Nuclei, 69 (2006)

Scintillating bolometers

SLIDE 21

Scintillation signal a/(e-,g) discrimination Heat signal Energy measurement

Ge plate

Lumineu R&D ZnMoO4 (313g) 141 h @ LSM

Expected bkg using CUORICINO contaminations bkg = 10-3 – 10-4 cts/(keV.kg.y)  T1/2 ~ 1026 yrs with only 1 cuoricino-like tower !

(instead of 19…)

3 experiments are starting:

LUMINEU: Zn100MoO4 crystal (France)
LUCIFER: Zn82Se crystal (Italy)
AMORE: 40Ca100MoO4 crystal (Korea)

Scintillating bolometers

SLIDE 22

136Xe TPC

Experiments

Several advantages to study Xenon

Simplest and least costly bb isotope to enrich
High bb2n half-life T1/2(136Xe) ~ T1/2(76Ge) ~ 2 1021 yrs
Natural candidate for TPC
Liq. TPC: EXO-200
Gas TPC: NEXT

Limitation:

2447 keV g-ray from 214Bi, very close to Qbb = 2462 keV

 The energy resolution must be better than ~15 keV (0.6%) at Qbb

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Liq. Xe TPC (200 kg Xe, 80% enrich. 136Xe)

Fiducial Volume  76.5 kg 136Xe Anti-correlation ionisation/scintillation  E = 3.6 % FWHM @ Qbb (E ~ 90 keV) 477.6 days (Sept. 2011 – Sept. 2013), 100 kg.yr

EXO-200 (WIPP, USA)

Bkg = (1.7  0.2 10-3 cts/(keV.kg.yr)  28 cts/(fwhm.yr) Radon (214Bi) dominant bkg  2447 keV g-ray from 214Bi, very close to Qbb = 2462 keV T1/2(bb0n) > 1.1 1025 yrs (90% C.L.)

Nature 510, 229 (2014)

Next step: Radon suppression Future project: nEXO with 5 tons 136Xe

SLIDE 24

Gas Xe TPC ~ 100 – 150 kg Xe gas, >90% enrich. 130Xe Electroluminescence technique for the TPC readout

NEXT (CANFRANC, SPAIN)

Better Energy resolution

Target: E = 1 % FWHM @ Qbb (E ~ 25 keV) Results of the NEXT-DEMO (a worst geometry): 1.7% FWHM at 511 keV (extrapolating to 0.77% FWHM at 2.5 MeV) has been obtained

Electron tracking by topological detection of the characteristic blob at the end of the track

NEXT-DEMO: electrons are identified in 98.5% of the cases JINST 8 P04002 (2013) (arXiv:1211.4838)

TDR, JINST 7 (2012) T06001

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Large Liquid Scintillators

Reuse the available large liquid scintillator n experiments by loading 136Xe or natTe KamLAND  KamLAND-Zen with 136Xe SNO  SNO+ with natTe

Advantage: one can measure a large mass of bb isotope
Limitation: the background is relatively high and the energy resolution is modest

SLIDE 26

Kamland-Zen

320 kg of 136Xe loaded in 13 tons Liq. Scint.

Xe concentration ~ 2.45 % (~700 kg 136Xe available in Kamioka mine)

Energy resolution fwhm = 10 % (~240 keV) at Qbb
Fiducial volume ~ 43 %

110Ag contamination

from Fukushima fallouts KamLAND-Zen Phase I

SLIDE 27

Kamland-Zen

KamLAND-Zen Phase II: 114.8 days (Dec. 2013 – May 2014) Next steps

KamLAND-Zen Next Phase (funded):

New inner balloon with 800 kg of load 130Xe  T1/2(bb0n) > 1026 yrs

KamLAND2-Zen

High energy resolution with pressurized Xenon

R<1m

Phase I: T1/2(0n) > 1.9 1025 y Phase II: T1/2(0n) > 1.3 1025 y Phases I+II: T1/2(0n) > 2.6 1025 y (90% C.L.)  383 kg 136Xe  LS purification  Xe purification  Film surface cleaning by LS flow  110Ag reduction factor > 10 bkg ~ 10 cts / (fwhm.yr)

SLIDE 28

SNO+

SNO detector filled with liquid scint. and load 130Te

First data foreseen end of 2014

130Te large nat. abundance (34%) : 0.3% natTe in 1 kt LS  ~ 800 kg 130Te

Fiducial volume ~20%  160 kg 130Te

High light yield of loaded Te liquid scintillator: Energy resolution E ~ 8 % at Qbb
High T1/2(bb2n) : bb2n bkg reduced
LS must be ultra radiopure in 238U and 232Th (~BOREXINO)
Solar 8B n is the ultimate bkg !

2 years of data

T(bb0n) = 6 1024 y

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NEMO

Tracko-Calo

SLIDE 30

 Direct reconstruction of the two electrons  Can distinguish a possible bb0n signal to a unknown g line  Direct measurement of the various components of background Bkg measured separately with dedicated event topology (e-, e+, g, a)

NEMO combines a tracking detector and a calorimeter

NEMO, a tracko-calo approach

SLIDE 31

Running from Feb. 2003 until Jan. 2011 in Modane Underground Laboratory (4800 m.w.e.)

NEMO-3 (LSM Modane)

Source: ~ 20 m2 of bb sources foils (~50 mg/cm2)

bb0n: 7 kg of 100Mo, 1 kg of 82Se bb2n: 0.4 kg 116Cd, 37 g 150Nd, 9 g 96Zr, 7 g 48Ca …

Tracking detector: drift cells in Geiger mode
Calorimeter: ~ 2000 plastic scint. + 5” PMTs

E/E ~ 15% (FWHM) @ 1 MeV Display of a bb0n candidate

SLIDE 32

34.3 kg.yr 100Mo, T1/2(0n) > 1.1 1024 yrs (90% C.L.)

NEMO-3 (LSM Modane)

700.000 bb events

ETOT(MeV)

cos

NEMO-3 bkg ≈ 0.4 cts/(kg.yr)

SLIDE 33

Source: ~ 5×3 m2 foil (40 mg/cm2): 82Se, 150Nd, 48Ca
Tracking: Drift cells in Geiger mode
Calorimeter: plastic scintillators + 8" PMT’s
20 modules to be installed in the future extension of LSM

NEMO-3 extrapolation 100 kg of 82Se  to reach T1/2(bb0n) ≥ 1026 years Bkg must be reduced by a factor ~ 40

SuperNEMO (LSM Modane)

First module (demonstrator) in construction Start data end 2015 in Modane Target: bkg < 10-2 cts/(kg.yr) in the bb0n ROI NEMO-3 bkg = 0.4 cts/(kg.yr)

SLIDE 34

CONCLUSIONS

2010 – 2020: New generation of bb experiments with few 100 kg of isotope
Experiments using 136Xe provided already first results with ~100 kg !
Kamland-Zen (using available large liquid scint. detector)
EXO-200 Liq. TPC
New experiments started
GERDA Phase 1: results in Summer 2013

Target bkg Phase-1 has been reached : bkg ~ 0.01 cts/(keV.kg.y) GERDA Phase 2 is starting: Target bkg ~ 0.001 cts/(keV.kg.yr) with 50 kg 82Ge

CUORE-0 : preliminary results bkg is at least 2 times too high
New experiments in construction
LUCIFER & LUMINEU: scintillating bolometer to reach bkg 0.001cts/(keV.kg.yr)

Can measure Se and Mo

SNO+ with natural Te: can start measuring ~ 160 kg of 130Te in 2015

And even larger mass (up to 8 tons ?) if the bkg is low enough

SuperNEMO with the direct detection of the two emitted e-
NEXT-100 (gaseous Xe TPC)

SLIDE 35

7 100 100 90 160 800 (0.3%) 8000 (3%) 380 800 19 12 230 200 30 20 50 200 Mass (kg) 2015 45 – 95 1 35 5 0.9

130Te

CUORE R&D 50 – 120 35 – 95 10 – 25 1. 0.7 10 0.15 0.15 2.7 5 0.9

82Se 100Mo 100Mo

ZnSe (1 tower) ZnMoO4 (1 tower) ZnMoO4 (19 towers) Published 2015 120 – 280 35 – 85 0.26 1 10 240 0.4

136Xe

Kamland-Zen Next-Phase 2014 2016 … … Few tens 200 0.2

130Te

SNO+ Published 2015 190 – 450 75 – 185 0.1 0.6 28 ? 90 0.5

130Xe

EXO-200 Rn removed 2014 60 – 150 1 0.15 3 0.9

76Ge

Majorana SuperNEMO NEXT-100 GERDA-I GERDA-II GERDA-III Experiment

82Se 82Se 150Nd 130Xe 76Ge

Isotope 0.2 0.3 0.9 0n 2015 ? ? 190 – 460 50 – 120 30 – 115 0.07 1 1 0.07 1 1 200 2015 60 – 145 1 0.5 25 Published 2014 ? 200 – 500 40 – 105 30 – 75 0.2 2. 10. 1.5 0.15 0.6 3.5 Start Data mn limit (eV) T1/2(0n) limit (1026 yrs) bkg@Qbb cts/(fwhm.y) E@Qbb (fwhm) (keV) 7 100 100 90 160 800 (0.3%) 8000 (3%) 380 800 19 12 230 200 30 20 50 200 Mass (kg) 2015 45 – 95 1 35 5 0.9

130Te

CUORE R&D 50 – 120 35 – 95 10 – 25 1. 0.7 10 0.15 0.15 2.7 5 0.9

82Se 100Mo 100Mo

ZnSe (1 tower) ZnMoO4 (1 tower) ZnMoO4 (19 towers) Published 2015 120 – 280 35 – 85 0.26 1 10 240 0.4

136Xe

Kamland-Zen Next-Phase 2014 2016 … … Few tens 200 0.2

130Te

SNO+ Published 2015 190 – 450 75 – 185 0.1 0.6 28 ? 90 0.5

130Xe

EXO-200 Rn removed 2014 60 – 150 1 0.15 3 0.9

76Ge

Majorana SuperNEMO NEXT-100 GERDA-I GERDA-II GERDA-III Experiment

82Se 82Se 150Nd 130Xe 76Ge

Isotope 0.2 0.3 0.9 0n 2015 ? ? 190 – 460 50 – 120 30 – 115 0.07 1 1 0.07 1 1 200 2015 60 – 145 1 0.5 25 Published 2014 ? 200 – 500 40 – 105 30 – 75 0.2 2. 10. 1.5 0.15 0.6 3.5 Start Data mn limit (eV) T1/2(0n) limit (1026 yrs) bkg@Qbb cts/(fwhm.y) E@Qbb (fwhm) (keV)

SUMMARY

N.M.E. from Duek et al. , Phys. Rev. D 83 (2011) In italic: performances already achieved Otherwise, numbers must be demonstrated

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EXTRA SLIDES

SLIDE 37

Isotope Experiment Technique Mass of isotope

bb0n

Bkg cts

/(kg.y.fwhm)

T1/2 (0n)

Limit (90%)

mn (eV)

Min. Max.

48Ca

CANDLES Scintillation 0.01 kg

~ 1

> 5.8 1022

3.55 9.91

76Ge

GERDA Ionisation

20 kg ~ 1 0.05 > 2.1 1025 0.2 0.5

82Se

NEMO-3 Tracko-calo

1 kg ~ 0.1 0.3 > 3.2 1023 0.85 2.08

100Mo

NEMO-3 Tracko-calo

7 kg ~ 0.1 0.5 > 1.0 1024 0.31 0.79

116Cd

Solotvina Scintillation

80 g ~ 1

> 1.7 1023

1.22 2.30

130Te

CUORICINO Bolometer

10 kg ~ 1 1.1 > 2.8 1024 0.27 0.57

136Xe

EXO-200 TPC Xe liq

160 kg ~ 0.4 0.025 > 1.1 1025 0.19 0.45

136Xe

Kamland-Zen

Liq. Scint.

130 kg ~ 0.5

110mAg

> 2.6 1025 0.13 0.31

150Nd

NEMO-3 Tracko-calo 0.04 kg

~ 0.1 0.5 >1.8 1022 2.35 8.65

Current best limits obtained in bb0n search

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Natural radioactive chains

SLIDE 39

Low Qbb Low 0n 34% nat. abundance Large available mass Low Qbb Bi g ray at

SLIDE 40

Experiment Isotop e Mass (kg) 0n E@Qbb (fwhm) (keV) bkg@Qbb cts/(fwhm. y) T1/2(0n) limit (1026 yrs) mn limit (eV) Start Data GERDA-I GERDA-II GERDA-III

76Ge

20 50 200 0.9 3.5 1.5 0.15 0.6 0.2 2. 10. 200 – 500 40 – 105 30 – 75 Publishe d 2014 ? Majorana

76Ge

30 0.9 3 0.15 1 60 – 150 2014 CUORE

130Te

200 0.9 5 35 1 45 – 95 2015 ZnSe (1 tower) ZnMoO4 (1 tower) ZnMoO4 (19 towers)

82Se 100Mo 100Mo

19 12 230 0.9 5 0.15 0.15 2.7 1. 0.7 10 50 – 120 35 – 95 10 – 25 R&D Kamland-Zen Next-Phase

136Xe

380 800 0.4 240 10 0.26 1 120 – 280 35 – 85 Publishe d 2015 SNO+

130Te

800 (0.3%) 8000 (3%) 0.2 200 Few tens … … 2014 2016 EXO-200 Rn removed

130Xe

160 0.5 90 28 ? 0.1 0.6 190 – 450 75 – 185 Publishe d 2015 NEXT-100

130Xe

90 0.3 25 0.5 1 60 – 145 2015

82Se

7 0.07 0.07 190 – 460 – – 2015 N.M.E. from Duek et al. , Phys. Rev. D 83 (2011)

SUMMARY

In italic: performances already achieved Otherwise, numbers must be demonstrated