double beta decay

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DOUBLE BETA DECAY

• Double beta decay at the borderline between nuclear and subnuclear physics (no border in my opinion)

• Nucleus acting as a microlaboratory to investigate fundamental problems in nuclear, subnuclear and astroparticle physics

• Great need of help from theorist and experimentalist in volved in low energy nuclear physics

• Double beta decay yesterday, today and tomorrow

• Advanced instrumentation

• Technical problems and particularly the reduction of the background (at the lowest value with respect to any other experiment)

Ettore Fiorini, Tokio June 8, 2007

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1. (A,Z) => (A,Z+2) + 2 e- + 2 -e => detected in ten nuclei

2. 2. (A,Z) => (A,Z+2) + 2 e- + ( …2,3 ) => Majoron3. 3. (A,Z) => (A,Z+2) + 2 e- => To be revealed by a pick => < m >≠ 0

The process

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u e -

d

d

e -W

u

e

e

2 - decay

W

0 - decay

e -

e -

d

du

u

W

We

e

Neutrinoless decay

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Suggested in general form by Maria Goepper Mayer just one year after the Fermi theory of beta decay. She was interested in the nuclear point of view

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Double Beta –Disintegration

M.Goeppert-Mayer, The John Hopkins University(Received May, 20 , 1935)

From the Fermi theory of disintegration the probability of simultameous emission of two electrons (and two neutrinos) has been calculated. The result is that this process occurs sufficiently rarely to allow an half-life of over 1017 years for a nucleus, even if its isobar of atomic number different by 2 were more stable by 20 times the electron mass

Double beta decay was at the beginning searched In the neutrinoless Double beta decay was at the beginning searched In the neutrinoless channel as a powerful way to search for channel as a powerful way to search for lepton number non lepton number non conservationconservation. Presently it is also considered as the most powerful way . Presently it is also considered as the most powerful way to investigate the value of the to investigate the value of the massmass of a of a Majorana neutrinoMajorana neutrino

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Oscillations indicate m2 ≠ 0, but unable to determine <m >

M.Ramsey-Musolf This.Conf.

M.Ramsey-Musolf This.Conf.

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What are we requesting to neutrinoless DBD?

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Also essential to detemine if is a Dirac or a Majorana Particle

Majorana =>1937

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The rate of neutrinoless DBD

= G(Q,Z) |Mnucl|2 <m>2

rate of DDB-0 Phase space Nuclear matrix elements

EffectiveMajorana neutrino mass

Nuclear matrix elements act as the value of the effective neutrino massVarious models have been applied:

Shell Model ( valid for low A nuclei, but now ri-elaborated also for nuclei of intermediate A) . High speed computer facilities needed

Quasiparticle Random Phase Approximation (QRPA) ,renormalized RQRPA ( to incorporate the Pauli principle)and pnQRPA. Quite sensitive to the particle-particle interaction parameter g pp

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Alice in the Wonderland

Two approaches:

V.A.Rodin et al Nucl.Phys.A 729 (2006) 107 => gpp from T

J.Suhonen Phys.Lett. B 607 (2005) 87 => gpp from T

Very recently

M.Kortelained & J.Suhonen 0705.0469 [nucl-th] “in Terra Infidelium” => calculation of NME for 76 Ge and 82Se where no single beta decay exists => uses T

Replaces Jastrow short range correlation with Unitarity Correlation Operator Method => Quite larger NME than Rodin et al

A.Faessler (letter) : Jastrow reduces 0.5±.1; Brueckner 0.65 ±.2; Unitarity Correlator Method (UCOM) 0.85 ±.1 , Deformation (150Nd maybe 76 Ge)

So far ~ 20 different calculations => 6 chosen by V.M.Gehman & S.Elliott hep-ph/0701099

Amicus Plato , sed magis amica veritas Plato is a friend, but truth even more

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Ro 48Ca 76Ge 82Se 100Mo 116Cd 128Te 130Te 136Xe 150Nd

1. pnQRPA 1.1 2.8 2.64 3.21 2.06 2.17 1.8 0.66 3.33

2. RQRPA 1.1 2.4 2.12 1.16 1.43 1.6 1.47 0.98 2.05

3. pnQRPA 1.2 3.33 3.44 2.97 3.75 3.49 4.64

4. pnQRPA 14.1 12.3 3.6 15.2 9.6 2. 28.9

5. Shell model 1.2 0.72 1.39 2.19 0.86 1.19 .75 .97

6. Shell model 1.2 1.6 1.7 0.3 1.9 2.0 1.6 .84

1. S.Simkovic et al Phys.Rev. C 60 (1999) 055502 2. V.A.Rodin et al Nucl. Phys. A 766 (2006) 1073. O.Civitarese and J.Suhonen , Nucl. Phys. A 729 (2003) 8674.K.Muto et al , Z.Phys.334 (1989) 1875. E.Caurrier et al, Nucl. Phys. A 654 (1999) 973c6. P. Vogel , Presentation to CINPAP 2006

Nuclear matrix elements

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Nucl Experiment % Q Enr Technique 0y <m) *

48Ca Elegant IV 0.19 4271 scintillator >1.4x1022 7-45

76Ge Heidelberg-Moscow 7.8 2039 87 ionization >1.9x1025 .3 – 1.24

76Ge IGEX 7.8 2039 87 Ionization >1.6x1025 .33 – 1.4

76Ge Klapdor et al 7.8 2039 87 ionization 1.2x1025 .44

82Se NEMO 3 9.2 2995 97 tracking >2.1.x1023 1.24-3.0

100Mo NEMO 3 9.6 3034 95-99 tracking >5.8x1023 .54-.93

116Cd Solotvina 7.5 3034 83 scintillator >1.7x1023 1.7 - ?

128Te Bernatovitz 34 2529 geochem >7.7 1024 1.1-1.5

130Te Cuoricino 33.8 2529 bolometric >3x1024 .16-.84.

136Xe DAMA 8.9 2476 69 scintillator >1.2x1024 1.1 -3.2

150Nd Irvine 5.6 3367 91 tracking >1.2x1021 3 - ?

Experimntal results

*H.Ejiri, Journ.Phys.Soc.of Japan, 74 (2005) 2101

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Nucleus 0y 1 2 3 4 5 6

48Ca >1.4x1022 2276Ge >1.9x1025 .47 .55 .41 .10 .97 .8476Ge >1.6x1025 .51 .60 .44 .11 1.1 .9176Ge 1.2x1025 .59 .69 .52 .13 1.2 1.182Se >2.1.x1023 2.2 2.9 1.8 .49 2.8 3.7100Mo >5.8x1023 .97 2.7 1.1 2.9 11116Cd >1.7x1023 2.4 3.5 1.4 2.7128Te >7.71024 1.8 2.5 .26 4.6 2.0130Te >3x1024 .7 .85 .37 .13 1.1 1.8136Xe >1.2x1024 2.9 2.0 .42 .96 2.6150Nd >1.2x1021 2.7 4.4 .31 1.0 .84

Rodin et al

Kort.& Suhon.

.52-.56 .22-.28

.57-.72 .24-.31

.65-.82 .28-.35

3.0-3.7 1.5-1.8

Conclusions of an experimentalist.=> many nuclei have to be investigated- Uncertaintiy on nuclear matrix elements- Environmenthal radioactivity produce many peaks which in principle could fake neutrinoles DBD events, but not in two or more different nuclei

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HM collaboration subset (KDHK): HM collaboration subset (KDHK): claim of evidence of 0claim of evidence of 0-DBD-DBD

In December 2001, 4 authors (KDHK) of the HM collaboration announce the discovery of neutrinoless DBD

/20 (y) = (0.8 – 18.3) 1025 y (1 1025 y b.v.)

M = 0.05 - 0.84 eV (95% c.l.)

54.98 kg•y 2.2

2001

71.7 kg•y 4

2004

skepticism in DBD community in 2001 better results in 2004

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Experimental approaches

Direct experiments

Source detector Source = detector

(calorimetric)

Geochemical experimentsi82Se = > 82Kr, 96Zr = > 96Mo (?) , 128Te = > 128Xe (non confirmed), 130Te = > 130Te

Radiochemical experiments238U = > 238Pu (non confirmed)

e-

e-

e-

e-

source

detector

detector

Source Detector

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Incident particle

absorber crystal

heat bath

Thermal sensor

Cryogenic detectors

J/K 3)D

T)(

Vm

V( 1944 C V

2TVCk E

@ 5 keV ~100 mk ~ 1 mg

<1 eV ~ 3 eV @ 2 MeV ~10 mk ~ 1 kg

<10 eV ~ keV

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Compound Isotopic abundance Transition energy

48CaF2 .0187 % 4272 keV

76Ge 7.44 " 2038.7 "

100MoPbO4 9.63 " 3034 "

116CdWO4 7.49 " 2804 "

130TeO2 34 " 2528 "

150NdF3 150NdGaO3

5.64 " 3368“

130Te has high transition energy and 34% isotopic abundance => enrichment non needed and/or very cheap. Any future extensions are possiblePerformance of CUORE, amply tested with CUORICINO

Other possible candidates for neutrinoless DBD Other possible candidates for neutrinoless DBD

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Two new experiments NEMO III and CUORICINO

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CUORICINO

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11 modules, 4 detector each,crystal dimension 5x5x5 cm3

crystal mass 790 g

4 x 11 x 0.79 = 34.76 kg of TeO2

2 modules, 9 detector each,crystal dimension 3x3x6 cm3

crystal mass 330 g

9 x 2 x 0.33 = 5.94 kg of TeO2

Search for the 2|o in 130Te (Q=2529 keV) and other rare events

At Hall A in the Laboratori Nazionali del Gran Sasso (LNGS)

18 crystals 3x3x6 cm3 + 44 crystals 5x5x5 cm3 = 40.7 kg of TeO2Operation started in the beginning of 2003 => ~ 4 months

Background .18±.01 c /kev/ kg/ a

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Present CUORICINO result (new)Present CUORICINO result (new)

11.8 kg year of 130Te

<m0.16 - .84 eV =>

3 x 1024 (90 % c.l.)

Klapdor et al m0.1- .9 eV

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Cosmological disfavoured region (WMAP)

Direct hierarchym2

12=

m2sol

Inverse hierarchym2

12= m2atm

“quasi” degeneracym1 m2 m3

With the same matrix elements the Cuoricino limit is 0.53 eV

Present Cuoricino region

Possible evidence (best value 0.39 eV)

H.V. Klapdor-Kleingrothaus et al., Nucl.Instrum.andMeth. ,522, 367 (2004).

Feruglio F. , Strumia A. , Vissani F. hep-ph/0201291

Arnaboldi et al., submitted to PRL, hep-ex/0501034 (2005).

DBD and Neutrino Masses

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Name A

(%)

Q Enr

(%)

B

c/y

T (year)

T <m>

CUORE 130Te 34 2533 35 3.5 7.x1026 B-in construction 9-57

GERDA 76Ge 7.8 2039 90 3.85 2x1027 I- 20 kg funded 29-94

Majorana 76Ge 7.8 2039 90 .6 4x1027 I-R&D 21-67

SuperNEMO 82Se 8.7 2995 90 1 21026 T-R&D 54-167

EXO 136Xe 8.9 2476 65 .55 1.3x1028 T-R&D -200kg 12-31

Moon-3 100Mo 9.6 3034 85 3.8 1.7x1027 T-R&D -MOON I 13-48

DCBA-2 150Nd 5.6 3367 80 1x1026 T-R&D -prototype 16-22

Candles 48Ca .19 4271 - .35 3x1027 S-R&D-prototype 29-54

GSO 160Gd 22 1730 - 200 1x1026 S - proposed 65-?

COBRA 115Cd 7.5 2805 90 1x1026 I- R&D -prototype 70 ?

XMASS 136Xe 8.9 2476 90 2x1027 S- proposed 24-62

SNOLAB+ 150Nd 5.6 3367 3.3x1027 S- proposed

Next generation experiments

B:bolometric, I:Ionization, S: Scintillation, T:Tracking

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Ionization

P.Grabmayr: This Conf.

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COBRA

Use large amount of CdZnTe Semiconductor Detectors

IONIZATION

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CANDLES

CaF2(pure)

liquid ScintillatorPMT(5")× 4

purewater

CaF2

LS

w.l. shifter

Reflector

L.Ogawa: This Conf.

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• 0n: 1000 events per

• year with 1% natural

• Nd-loaded liquid

• scintillator in SNO++

Test <m> = 0.150 eV

maximum likelihood statistical test of the shape to extract 0 and 2 components…~240 units of 2 significance after only 1 year!

simulation:one year of data

Scintillation

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Scintillation

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Tracking SUPERNEMO

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MOONAn Option: Multilayer scintillator plates and thin MWPC tracking chambers with thin source filmFor , E-resolution 2.2 % forN ~ 5 ton year,

<m> ~ 47 – 32 meV for 100Mo – 82Se 90 % CL

Tracking chamber

H. Ejiri, et al., PRL, 85, 2000. H. Ejiri et al., Czech. J. Phsy. 54, .

Detector ≠ sourceSelect sourcesSolar as well

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Principle of DCBADCBA (DDrift CChamber BBeta-ray AAnalyzer)

Gas:He(85%)+CO2(15%)

Y

Z X

Pickup

100 mV/div 100 ns/div

Anode

ee mmpT

rBp

2/122 )(

,3.0cos150Nd→150Sm+2e-

p (MeV/c): momentum, r (cm): radius,

: pitch angle, B (kG): magnetic field,

me (MeV/c2): electron mass

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■ conceptconcept: scale Gotthard experiment adding Ba taggingBa tagging to suppress background (136Xe136Ba+2e)

■ single Ba detected by optical spectroscopy

■ two options with 63% enriched Xe ▶High pressure Xe TPC High pressure Xe TPC ▶LXe TPC + scintillation LXe TPC + scintillation

■ calorimetry + trackingcalorimetry + tracking■ expected bkg only by -2

▶energy resolution E = 2%

Present R&DPresent R&D■ Ba+ spectroscopy in HP Xe / Ba+ extr. ■ energy resolution in LXe (ion.+scint.)■ Prototype scale:► 200 kg enriched L136Xe without tagging► all EXO functionality except Ba id► operate in WIPP for ~two years ■Protorype goals:►Test all technical aspects of EXO

(except Ba id)►Measure 2 mode►Set decent limit for 0 mode

(probe Heidelberg- Moscow)

22PP1/21/2

44DD3/23/222SS1/21/2

493 nm493 nm650 nm650 nm

metastable metastable 47s47s

LXe TPCLXe TPC

EXOEXO

Full scale experiment at WIPP or Full scale experiment at WIPP or SNOLABSNOLAB■10 t10 t (for LXe ⇒ 3 m3)

▶b = 4×10-3 c/keV/ton/y▶1/21/2 1.31.3××10102828 y y in 5 years▶⟨⟨mm 0.013 0.013 ÷÷ 0.037 eV 0.037 eV

Tracking

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80 cm

19 towers with13 planes of4 crystals each

19 towers with13 planes of4 crystals each

CUORECUORECryogenic Underground Observatory for Rare EventsCryogenic Underground Observatory for Rare Events

Array of 988 TeO2 detectors (750 g each)

M = 741 kg of TeO2 = 203 kg of 130Te

Array of 988 TeO2 detectors (750 g each)

M = 741 kg of TeO2 = 203 kg of 130Te

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CUORE expected sensitivityCUORE expected sensitivity

disfavoured by cosm

ology

11-576.5 × 1026510-3

19-1002.1 × 1026510-2

<m> [meV]T1/2 [y]

[keV]b (counts/keV/kg/y)

11-576.5 × 1026510-3

19-1002.1 × 1026510-2

<m> [meV]T1/2 [y]


11-576.5 × 1026510-3

19-1002.1 × 1026510-2

<m> [meV]T1/2 [y]


11-576.5 × 1026510-3

19-1002.1 × 1026510-2

<m> [meV]T1/2 [y]


Strumia A. and Vissani F. hep-ph/0503246

In 5 years:In 5 years:

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Neutrino oscillations m2 ≠0 <m> finite for at least one neutrino

Neutrinoless double beta decay would indicate if neutrino is a lepton violating Majorana particle and would allow in this case to determine <mn> and the hierachy of oscillations.

This process has been indicated by an experiment (Klapdor) with a value of ~0.44 eV but has not been confirmed

Future experiments on neutrinoless double beta decay will allow to reach the sensitivity predicted by oscillations in the inverse hierarchy scheme

Help us from low energy nuclear physics both with theory and experiments

The multidisciplinarity of searches on double beta decay involves nuclear and e subnuclear physics, astrophysics , radioactivity, material science, geochronology etc. It could help in explaining the particle-antiparticle asymmetry of the Universe

CONCLUSIONS

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DAMA results on DAMA results on decay modes decay modes

Experimental limits on T1/2 obtained by DAMA (red) and by previous experiments (blue) [limits at 90% C.L. except for 2+0 in 136Ce and 2-0 in 142Ce - 68% C.L.]

…. and in progress

Ro

ma2

,Ro

ma1

,LN

GS

,IH

EP

/Bei

jin

g+

in

som

e a

cti

vit

ies:

INR

-Kie

v

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Resolution of the 5x5x5 cm3 (~ 760 g ) crystals

:0.8 keV FWHM @ 46 keV

1.4 keV FWHM @ 0.351 MeV




(the best spectrometer ever realized)

Energy [keV]

Cou

nts

210Po line

double beta decay

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