Comments on Neutrinoless Double Beta Decay Experiments

Huan Zhong Huang (黄焕中 )Department of Physics and Astronomy

University of California, Los Angeles 90095huang@physics.ucla.edu

OCPA Underground Sciences WorkshopHong Kong, July 21-23 2008

Thanks to F. Avignone, S.J. Freedman, E. Fiorini, R. Maruyama

Neutrino Physics Program

Critical Questions for Future Neutrino Physics Program

1) Are neutrinos their own anti-particles?Dirac or Majorana neutrinos

2) What are the scale of neutrino masses and thehierarchy of the neutrino mass ordering?

3) What is the remaining neutrino mixing angle 13?

4) Do neutrinos violate the CP symmetry and contribute to the matter-antimatter asymmetry?

Massive Neutrinos: Majorana or Dirac?

Lorentz Invariance: massive particle velocity < speed of light c

Momentum

spinLeft-handed LH

Right-handed RH

(Lab)

(Speed-of-light Frame)

Majorana Neutrino Neutrino=anti-neutrino

Dirac Neutrino Neutrino and anti-neut distinct

LH RH

Boost

CPT

LH LH RHRH

Boost

CPT CPT

e

e–

e–

e

(A,Z)

(A,Z+2)

W

W

(A,Z) (A,Z+2) + 2e– + 2e

2: T1/2 ≥ 1018y

(A,Z)

(A,Z+2)

(A,Z+1)

Even-even nucleus2

1935

Double Beta Decay

M. Goeppert-Mayer

Dirac or Majorana Neutrinos?0

ee–

e–e

(A,Z)

(A,Z+2)

W

W

(A,Z) (A,Z+2) + 2e–

0: T1/2 ≥ 1025y

1937

Majorana neutrino = anti-neutrinoLepton Number violation !

Measuring Neutrino Masses

3

1

22||i

iei mU

3

1

2||i

iiei mU

1) Direct Measurement tritium decays E0 = 18.6 keV

<m> =

2) Effective Majorana Mass

<m> =

3) Precise Cosmological Measurement <m> =

3

1iim

i – CP phase for neutrinos

The actual range of m depends on the NME !There is no clear issue identified regarding the

experimental data.

The Cuoricino experimentThe Cuoricino experiment• 62 TeO2 bolometers

• Total detector mass:M ~ 11 kg 130Te ~ 5x1025 130Te nuclides

• Deep underground in the Gran Sasso Laboratory (Italy) (3500 m.w.e.)

• Started in 2003, currently the largest operated bolometric experiment

Cuoricino Results Neither Support Nor Rule Cuoricino Results Neither Support Nor Rule Out Heidelberg-Moscow ClaimOut Heidelberg-Moscow Claim

Background in region0.18 0.01 c/keV/kg/y

Average resolution @ 2615keV~ 8keV

Results for half lifeand Majorana mass (90%

c.l.):

T1/20 (130Te) > 3.1 x 1024 y

m < 200 - 680 meV (*)

(*) using NME from Rodin et al, Nucl. Phys. A 776 (2006) and

erratum arXiv::nucl-th/0706.4304Cuoricino demonstrates the feasibility of a large scale bolometric detector with good energy resolution

Background reduction is being worked on for scaled up CUORE

PRELIMINARY Updated Aug

2007Tot exposure = 15.53 kg y 130Te

60Co

The Constraint from Cosmology Competitive

Model Dependent ! G.L. Fogli et al, hep-ph/0805.2517

Cosmological Data Set (at 2)CMB < 1.19 eVCMB+HST+SN-Ia < 0.75 eV

CMB+HST+SN-Ia+BAO < 0.60 eV CMB+HST+SN-Ia+BAO+Ly < 0.19 eV

CMB – WMAP 5-year, ACBAR, VSA, CBI, BOOMERANGHST – Hubble Space Telescope h=0.75+-0.07SN-Ia – SNLA (The SuperNova Legacy Survey)BAO – Baryonic Acoustic Oscillation (WMAP)Ly – Small Scale Primordial Spec from Lyman- forest coulds

48Ca48Ti 4.271 0.18776Ge76Se 2.040 7.882Se82Kr 2.995 9.296Zr96Mo 3.350 2.8100Mo100Ru 3.034 9.6110Pd110Cd 2.013 11.8116Cd116Sn 2.802 7.5124Sn124Te 2.228 5.64130Te130Xe 2.533 34.5136Xe136Ba 2.479 8.9150Nd150Sm 3.367 5.6

Candidate for Double beta DecaysQ (MeV) Abund.(%)

Major 0 Experiments(scalable to ~1 ton now or planned)

0 Experiments

-- CUORE 130Te

-- MAJORANA/GERDA 76Ge

-- EXO 136Xe

Essential to Measure 0 for SeveralElements !!

US-Italy CollaborationUS-Italy Collaboration CUORE @ LNGSCUORE @ LNGS

CUORE R&D (Hall C)

CUORICINO - CUORE (Hall A)

Underground National Laboratory of Gran Sasso

L'Aquila – ITALY3500 m.w.e.

CUORECUORE

80 cm

CUORE: Cryogenic Underground Observatory for Rare Events will be a tightly packed array of 988 Bolometers - M ~ 200 kg of 130Te

• Operated at Gran Sasso laboratory

• Special cryostat built w/ selected materials

• Cryogen-free dilution refrigerator• Shielded by several lead shields

19 CUORICINO-like towers with 13 planes of 4 crystals each

Bolometer

Heat sink: ~8-10 mKThermal coupling: TeflonThermometer: NTD Ge thermistorAbsorber: TeO2 crystal

Heat sink: ~8-10 mKThermal coupling: TeflonThermometer: NTD Ge thermistorAbsorber: TeO2 crystal

TeO2 Bolometer: Source = DetectorTeO2 Bolometer: Source = Detector

Signal from NTD Ge Thermistor

Energy resolution of a TeO2 crystal of 5x5x5 cm3 (~ 760 g )

Energy [keV]

Cou

nts

210Po line

0.8 keV FWHM @ 46 keV

1.4 keV FWHM @ 0.351 MeV

2.1 keV FWHM @ 0.911 MeV

2.6 keV FWHM @ 2.615 MeV

3.2 keV FWHM @ 5.407 MeV

the best spectrometer so

far

Scaling CUORE from CUORICINO

Background Reduction is the Key

CUORICINO – Surface Related Background CUORE -- Crystal Production -- TeO2 Material QA for Crystal Production -- Crystal Processing QA -- Improved Surface Cleaning Procedure

Crystal Support Structure (Cu) -- New/Improved Surface Cleaning Procedure

Note – CUORICINO/CUORE Has Excellent Shielding (Roman Lead)

APS Neutrino Study 2004

Expected Sensitivity of the CUORE Experiment

General CommentsCUORE-- 130Te-- Excellent Energy Resolution (FWHM 0.3%)-- Cost Effective -- Background Elimination Challenging-- Data-Taking Early 2011

GERDA/MAJORANA -- 76Ge-- Ultra-Low Background Possible-- Detector Segmentation and Pulse Shape

Analysis Possible-- Very Costly !

EXO -- 136Xe-- Easy to Scale Up-- Ba+ Tagging Challenging / FWHM ~3.4%

Interdisciplinary SciencesThree Overarching Themes

-- APS multidivisional neutrino study Neutrino Matrix – physics/0411216

1) Neutrinos and the New Paradigm-- neutrino masses, Dirac/Majorana and CP violation

beyond the Standard Model 2) Neutrinos and the Unexpected

-- Many discoveries in recent years, what surprises andextraordinary properties ahead?

3) Neutrinos and Cosmos-- # of neutrinos, neutrino masses – large structures

CP violation – matter/anti-matter asymmetry

CUORE CollaborationCUORE Collaboration

University of California at BerkeleyA. Bryant2, M.P. Decowski2 , M.J. Dolinski3 , S.J. Freedman2,

E.E. Haller2, L. Kogler2, Yu.G. Kolomensky2

University of South CarolinaF.T. Avignone III, I. Bandac, R. J. Creswick, H.A. Farach,

C. Martinez, L. Mizouni, C. Rosenfeld

Lawrence Berkeley National Laboratory J. Beeman, E. Guardincerri, R.W. Kadel, A.R. Smith, N. Xu

Lawrence Livermore National LaboratoryK. Kazkaz, E.B. Norman4, N. Scielzo

University of California, Los AngelesH. Z. Huang, S. Trentalange, C. Whitten Jr.

University of Wisconsin, MadisonL.M. Ejzak, K.M. Heeger, R.H. Maruyama, S. Sangiorgio

California Polytechnic State University T.D. Gutierrez

2also LBNL3also LLNL

4also UC Berkeley

Universita’ di Milano-Bicocca5

C. Arnaboldi, C. Brofferio, S. Capelli, M. Carrettoni, M. Clemenza, E. Fiorini, S. Kraft, C. Maiano, C. Nones, A. Nucciotti, M. Pavan,

D. Schaeffer, M. Sisti, L. Zanotti

Sezione di Milano dell’INFNF. Alessandria, L. Carbone, O. Cremonesi, L. Gironi, G. Pessina,

S. Pirro, E. Previtali

Politecnico di MilanoR. Ardito, G. Maier

Laboratori Nazionali del Gran Sasso M. Balata, C. Bucci, P. Gorla, S. Nisi, E. L. Tatananni, C. Tomei, C. Zarra

Universita’ di Firenze and Sezione di Firenze dell’INFNM. Barucci, L. Risegari, G. Ventura

Universita’ dell’Insubria5

E. Andreotti, L. Foggetta, A. Giuliani, M. Pedretti, C. Salvioni

Universita di Genova S. Didomizio6, A. Giachero7, P. Ottonello6, M. Pallavicini6

Laboratori Nazionali di LegnaroG. Keppel, P. Menegatti, V. Palmieri, V. Rampazzo

Universita di Roma La Sapienza and Sezione di Roma dell’INFNF. Bellini, C. Cosmelli, I. Dafinei, R. Faccini, F. Ferroni, C. Gargiulo,

E. Longo, S. Morganti, M. Olcese, M. Vignati

Universita’ di Bologna and Sezione di Bologna dell’INFNM. M. Deninno, N. Moggi, F. Rimondi, S. Zucchelli

University of ZaragozaM. Martinez

Kammerling Onnes Laboratory, Leiden UniversityA. de Waard, G. Frossati

Shanghai Institute of Applied Physics (Chinese Academy of Sciences)

X. Cai, D. Fang, Y. Ma, W. Tian, H. Wang

5also Sezione di Milano dell’INFN6also Sezione di Genova dell’INFN

7also LNGS

Full estimated range of M within QRPA framework and comparison with NSM (higher order currents now included in NSM) – P. Vogel

Double Beta Decay CandidatesNormal beta-decay is energetically forbidden, while double beta-decay from (A,Z) (A, Z+2) is energetically allowed:

A, Z

A, Z+1

A, Z+2

A, Z+30+

0+

(A=even, Z=even)

48Ca, 70Zn, 76Ge, 80Se, 86Kr, 96Zr, 100Mo, 116Cd, 130Te, 136Xe, 150Nd

Some candidates:

CUORE

Array of 988 TeO2 crystals

• 19 Cuoricino-like “towers”

• 13 levels, 4 crystals each

• 5x5x5 cm3 (750 g each)

• Low conductance Teflon insulators

• OFHC Cu structure

• Crystals equipped with NTDs

• Suspended from cold stage

• Mechanically isolated

OGHC-Oxygen Free High ConductivityNTD-Neutron Transmutation Doped

Neutrino Masses and Hierarchy

Normal Inverted

Cosmogenic Co from Te