1. 1 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

2. 2 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  ) => Majoron 3.3. (A,Z) => (A,Z+2) + 2 e - => To be revealed by a pick => ≠ 0 The process

3. 3 0 -  decay e - e - d d u u W W e e Neutrinoless  decay

4. 4 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

5. 5 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 10 17 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 channel as a powerful way to search for lepton number non conservation. Presently it is also considered as the most powerful way to investigate the value of the mass of a Majorana neutrino Double beta decay was at the beginning searched In the neutrinoless channel as a powerful way to search for lepton number non conservation. Presently it is also considered as the most powerful way to investigate the value of the mass of a Majorana neutrino

6. 6 Oscillations indicate  m 2 ≠ 0, but unable to determine M.Ramsey-Musolf This.Conf.

7. 7

8. 8 What are we requesting to neutrinoless DBD?

9. 9 Also essential to detemine if is a Dirac or a Majorana Particle Majorana =>1937

10. 10 The rate of neutrinoless DBD  = G(Q,Z) |M nucl | 2 2 rate of DDB -0 Phase spaceNuclear matrix elements EffectiveMajorana neutrino mass Nuclear matrix elements act as the value of the effective neutrino mass Various 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

11. 11 Alice in the Wonderland Two approaches: V.A.Rodin et al Nucl.Phys.A 729 (2006) 107 => g pp from T   J.Suhonen Phys.Lett. B 607 (2005) 87 => g pp from T    Very recently M.Kortelained & J.Suhonen 0705.0469 [ nucl-th ] “in Terra Infidelium” => calculation of NME for 76 Ge and 82 Se 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 ( 150 Nd 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

12. 12 Ro 48 Ca 76 Ge 82 Se 100 Mo 116 Cd 128 Te 130 Te 136 Xe 150 Nd 1. pnQRPA1.12.82.643.212.062.171.80.663.33 2. RQRPA1.12.42.121.161.431.61.470.982.05 3. pnQRPA1.23.333.442.973.753.494.64 4. pnQRPA14.112.33.615.29.62.28.9 5. Shell model1.20.721.392.190.861.19.75.97 6. Shell model1.21.61.70.31.92.01.6.84 1. S.Simkovic et al Phys.Rev. C 60 (1999) 055502 2. V.A.Rodin et al Nucl. Phys. A 766 (2006) 107 3. O.Civitarese and J.Suhonen, Nucl. Phys. A 729 (2003) 867 4.K.Muto et al, Z.Phys.334 (1989) 187 5. E.Caurrier et al, Nucl. Phys. A 654 (1999) 973c 6. P. Vogel, Presentation to CINPAP 2006 Nuclear matrix elements

13. 13 NuclExperiment%Q  EnrTechnique  0  y  <m ) * 48 CaElegant IV0.194271scintillator>1.4x10 22 7-45 76 GeHeidelberg-Moscow7.8203987ionization>1.9x10 25.3 – 1.24 76 GeIGEX7.8203987Ionization>1.6x10 25.33 – 1.4 76 GeKlapdor et al7.8203987ionization1.2x10 25.44 82 SeNEMO 39.2299597tracking>2.1.x10 23 1.24-3.0 100 MoNEMO 39.6303495-99tracking>5.8x10 23.54-.93 116 CdSolotvina7.5303483scintillator>1.7x10 23 1.7 - ? 128 TeBernatovitz342529geochem >7.7  10 24 1.1-1.5 130 TeCuoricino33.82529bolometric>3x10 24.16-.84. 136 XeDAMA8.9247669scintillator>1.2x10 24 1.1 -3.2 150 NdIrvine5.6336791tracking>1.2x10 21 3 - ? Experimntal results *H.Ejiri, Journ.Phys.Soc.of Japan, 74 (2005) 2101

14. 14 Nucleus  0  y  123456 48 Ca>1.4x10 22 22 76 Ge>1.9x10 25.47.55.41.10.97.84 76 Ge>1.6x10 25.51.60.44.111.1.91 76 Ge1.2x10 25.59.69.52.131.21.1 82 Se>2.1.x10 23 2.22.91.8.492.83.7 100 Mo>5.8x10 23.972.71.12.911 116 Cd>1.7x10 23 2.43.51.42.7 128 Te >7.7  10 24 1.82.5.264.62.0 130 Te>3x10 24.7.85.37.131.11.8 136 Xe>1.2x10 24 2.92.0.42.962.6 150 Nd>1.2x10 21 2.74.4.311.0.84 Rodin et al Kort.& Suhon..52-.56.22-.28.57-.72.24-.31.65-.82.28-.35 3.0-3.71.5-1.8 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

15. 15 HM collaboration subset (KDHK): claim of evidence of 0 -DBD In December 2001, 4 authors (KDHK) of the HM collaboration announce the discovery of neutrinoless DBD   /2 0 (y) = (0.8 – 18.3)  10 25 y (1  10 25 y b.v.)  M   = 0.05 - 0.84 eV (95% c.l.) 54.98 kgy 2.2  2001 71.7 kgy 4  2004 skepticism in DBD community in 2001 better results in 2004

16. 16 Experimental approaches Direct experiments Source  detector Source = detector (calorimetric) Geochemical experiments i82 Se = > 82 Kr, 96 Zr = > 96 Mo (?), 128 Te = > 128 Xe (non confirmed), 130 Te = > 130 Te Radiochemical experiments 238 U = > 238 Pu (non confirmed) e-e- e-e- e-e- e-e- source detector Source  Detector

17. 17 Incident particle absorber crystal heat bath Thermal sensor Cryogenic detectors  @ 5 keV ~100 mk ~ 1 mg <1 eV ~ 3 eV @ 2 MeV ~10 mk ~ 1 kg <10 eV ~ keV

18. 18 CompoundIsotopic abundanceTransition energy 48 CaF 2.0187 %4272keV 76 Ge7.44 "2038.7 " 100 MoPbO 4 9.63 "3034 " 116 CdWO 4 7.49 "2804 " 130 TeO 2 34 "2528 " 150 NdF 3 150 NdGaO 3 5.64 "3368“ 130 Te has high transition energy and 34% isotopic abundance => enrichment non needed and/or very cheap. Any future extensions are possible Performance of CUORE, amply tested with CUORICINO Other possible candidates for neutrinoless DBD

19. 19

20. 20 Two new experiments NEMO III and CUORICINO

21. 21 CUORICINO

22. 22 11 modules, 4 detector each, crystal dimension 5x5x5 cm 3 crystal mass 790 g 4 x 11 x 0.79 = 34.76 kg of TeO 2 2 modules, 9 detector each, crystal dimension 3x3x6 cm 3 crystal mass 330 g 9 x 2 x 0.33 = 5.94 kg of TeO 2 Search for the 2  | o in 130 Te (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 TeO2 Operation started in the beginning of 2003 => ~ 4 months Background.18±.01 c /kev/ kg/ a

23. 23

24. 24 Present CUORICINO result (new) 11.8 kg year of 130 Te  3 x 10 24 (90 % c.l.) Klapdor et al m 0  .1-.9 eV

25. 25 Cosmological disfavoured region (WMAP) Direct hierarchy  m 2 12 =  m 2 sol Inverse hierarchy  m 2 12 =  m 2 atm “quasi” degeneracy m 1  m 2  m 3 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.and Meth.,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

26. 26 NameA (%) Q  Enr (%) B c/y T  (year) T CUORE 130 Te342533353.57.x10 26 B-in construction9-57 GERDA 76 Ge7.82039903.852x10 27 I- 20 kg funded29-94 Majorana 76 Ge7.8203990.64x10 27 I-R&D21-67 SuperNEMO 82 Se8.72995901210 26 T-R&D54-167 EXO 136 Xe8.9247665.551.3x10 28 T-R&D -200kg12-31 Moon-3 100 Mo9.63034853.81.7x10 27 T-R&D -MOON I13-48 DCBA-2 150 Nd5.63367801x10 26 T-R&D -prototype16-22 Candles 48 Ca.194271-.353x10 27 S-R&D-prototype29-54 GSO 160 Gd221730-2001x10 26 S - proposed65-? COBRA 115 Cd7.52805901x10 26 I- R&D -prototype70 ? XMASS 136 Xe8.92476902x10 27 S- proposed24-62 SNOLAB+ 150 Nd5.633673.3x10 27 S- proposed Next generation experiments B:bolometric, I:Ionization, S: Scintillation, T:Tracking

27. 27 Ionization P.Grabmayr: This Conf.

28. 28 COBRA Use large amount of CdZnTe Semiconductor Detectors IONIZATION

29. 29 CANDLES L.Ogawa: This Conf.

30. 30 0n: 1000 events per year with 1% natural Nd-loaded liquid scintillator in SNO++ Test = 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

31. 31 Scintillation

32. 32 Tracking SUPERNEMO

33. 33 MOON An Option: Multilayer scintillator plates and thin MWPC tracking chambers with thin  source film For   , E-resolution  2.2 % for  N ~ 5 ton year, ~ 47 – 32 meV for 100 Mo – 82 Se 90 % CL Tracking chamber  H. Ejiri, et al., PRL, 85, 2000. H. Ejiri et al., Czech. J. Phsy. 54,. Detector ≠  source Select  sources Solar as well

34. 34 DCBA DCBA Principle of DCBA (D rift C hamber B eta-ray A nalyzer ) Gas:He(85%)+CO 2 (15%) Y ZX Pickup 100 mV/div 100 ns/div Anode 150 Nd→ 150 Sm+2e - p (MeV/c): momentum, r (cm): radius, : pitch angle, B (kG): magnetic field, m e (MeV/c 2 ): electron mass

35. 35 ■ concept Ba tagging ■ concept: scale Gotthard experiment adding Ba tagging to suppress background ( 136 Xe 136 Ba+2e) ■ single Ba detected by optical spectroscopy ■ two options with 63% enriched Xe ▶ High pressure Xe TPC ▶ LXe TPC + scintillation ■ calorimetry + tracking ■ ■ expected bkg only by -2 ▶ energy resolution E = 2% Present R&D ■ Ba + spectroscopy in HP Xe / Ba + extr. ■ energy resolution in LXe (ion.+scint.) ■ Prototype scale: ► 200 kg enriched L 136 Xe 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) 2 P 1/2 4 D 3/2 2 S 1/2 493 nm 650 nm metastable47s LXe TPC EXO Full scale experiment at WIPP or SNOLAB ■ 10 t ■ 10 t (for LXe ⇒ 3 m 3 ) ▶ b = 4×10 -3 c/keV/ton/y ▶ 1/2 1.3×10 28 y ▶ 1/2 1.3×10 28 y in 5 years ▶ 〈 m 〉 0.013 ÷ 0.037 eV Tracking

36. 36 80 cm 19 towers with 13 planes of 4 crystals each 19 towers with 13 planes of 4 crystals each CUORE Cryogenic Underground Observatory for Rare Events Array of 988 TeO 2 detectors (750 g each) M = 741 kg of TeO 2 = 203 kg of 130 Te Array of 988 TeO 2 detectors (750 g each) M = 741 kg of TeO 2 = 203 kg of 130 Te

37. 37

38. 38

39. 39 CUORE expected sensitivity disfavoured by cosmology Strumia A. and Vissani F. hep-ph/0503246 In 5 years:

40. 40 Neutrino oscillations   m 2 ≠0  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 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

41. 41

42. 42 DAMA results on  decay modes Experimental limits on T 1/2 obtained by DAMA (red) and by previous experiments (blue) [limits at 90% C.L. except for 2  + 0 in 136 Ce and 2  - 0 in 142 Ce - 68% C.L.] …. and in progress Roma2,Roma1,LNGS,IHEP/Beijing + in some activities: INR-Kiev

43. 43

44. 44 Resolution of the 5x5x5 cm3 (~ 760 g ) crystals : 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 ever realized) Energy [keV] Counts 210 Po  line