1. DBD matrix elements Welcome and aim of the workshop Experimental situation Outcome

2. (A,Z)  (A,Z+2) + 2 e - + 2 e 2  (A,Z)  (A,Z+2) + 2 e - 0  - 0+0+ 0+0+ 1+1+ (A,Z) (A,Z+1) (A,Z+2) 0  : Only possible if neutrinos are Majorana particles In nature there are 35 isotopes Double beta decay 2  : Seen in 9 isotopes, important for nuclear physics input

3. 3 Flavour oscillations (PMNS) Analogous to CKM matrix Double beta decay: Effective Majorana neutrino mass relative CP phases =  1

4. Neutrino mass hierarchies NORMALINVERTED

5. „inverted“ mass hierarchy m 3 < m 1 < m 2 hierarchical quasi-degenerate Neutrino mass schemes and DBD „normal“ mass hierarchy m 1 <m 2 <m 3 almost degenerate neutrinos m 1 ≈ m 2 ≈ m 3

6. Spectral shapes Sum energy spectrum of both electrons 0  : Peak at Q-value of nuclear transition T 1/2  a  (Mt/  EB) 1/2 1 / T 1/2 = PS * ME 2 * (m / m e ) 2 Measured quantity: Half-life Dependencies (BG limited) link to neutrino mass

7. Heidelberg -Moscow Five Ge diodes (overall mass 10.9 kg) Five Ge diodes (overall mass 10.9 kg) isotopically enriched ( 86%) in 76 Ge isotopically enriched ( 86%) in 76 Ge Lead box and nitrogen flushing of the detectors Lead box and nitrogen flushing of the detectors Digital Pulse Shape Analysis (factor 5 reduction) Peak at 2039 keV Digital Pulse Shape Analysis (factor 5 reduction) Peak at 2039 keV Evidence ? H.V. Klapdor-Kleingrothaus et al, PLB 586,198 (2004)

8. Running experiments DBD Q-value CUORICINO: cryogenic bolometers 40.7 kg TeO 2 Future: CUORE 760 kg TeO 2 approved NEMO-3: TPC 10 kg enriched foils, 6 kg 100 Mo Idea: Super-NEMO (100 kg) T 1/2 > 1.8 x 10 24 yr (90% CL) Arnaboldi et al, hep-ex/050134 T 1/2 > 3.1 x 10 23 yr (90% CL) Arnold et al, Pis‘ma v ZhETF, 80, 429 (2004)

9. The 64 detector array Aim for next 2 years: The next step towards a large scale experiment, Scalable modular design, explore coincidences Include: Cooling Nitrogen flushing Mass factor 16 higher, about 0.4 kg CdZnTe Physics: - Can access 2 ECEC in theoretically predicted region -Precision measurement of 113Cd - New limits Part of the detectors at Dortmund

10.  0  Experimental Situation ExperimentIsotopeT 1/2 0  (y) (eV) You Ke et al. 1998 48 Ca > 9.5  10 21 (76%) < 8.3 Klapdor-Kleingrothaus 2001 76 Ge > 1.9  10 25 < 0.35 Aalseth et al 2002 > 1.57  10 25 < 0.33 - 1.35 Arnold et al. 2004 82 Se> 1.3 x 10 23 < 1.5-3.1 Arnold et al. 2004 100 Mo >3.1  10 23 < 0.33-0.84 Danevich et al. 2000 116 Cd > 1  10 23 < 2.2 Bernatowicz et al. 1993 130/128 Te* (3.52  0.11)  10 -4 < 1.1 – 1.5 Bernatowicz et al. 1993 128 Te* > 7.7  10 24 < 1.1 – 1.5 Arnaboldi et al. 2005 130 Te > 1.8  10 24 < 0.5 – 1.1 Luescher et al. 1998 136 Xe > 4.4  10 23 < 1.8 – 5.2 Belli et al. 2001 136 Xe > 7  10 23 < 1.4 – 4.1 De Silva et al. 1997 150 Nd > 1.2  10 21 < 3 Danevich et al. 2001 160 Gd > 1.3  10 21 < 26 2 main experimental approaches : Active Source Active Source Passive Source Passive Source Best 0 2  results involve active source experiments

11.  2  Experimental situation IsotopeT 1/2 2 (y) M GT 2 (MeV -1 ) 48 Ca (4.25  1.6)  10 19 0.05 76 Ge (1.38  0.14)  10 21 0.15 82 Se (8.9  1.0)  10 19 0.10 96 Zr (1.43 +3.4 -0.8 )  10 19 0.12 100 Mo (8.2  0.6)  10 18 0.22 100 Mo(0 +* ) (6.8  1.2)  10 20 0.1 116 Cd (3.2  0.3)  10 19 0.12 128 Te (7.2  0.3)  10 24 0.025 130 Te (2.7  0.1)  10 21 0.017 136 Xe > 8.1  10 20 <0.03 150 Nd (7.0 +12.0 -1.0 )  10 18 0.07 238 U (2.0  0.6)  10 21 0.05 2 nd order weak process Severe test for nuclear matrix elements calculations Weighted average of the most recent experiments i)average asymmetryc bars ii)add systematic errors in quadrature Elliott and Vogel 2002 Nuclear structure effects cause variations by a factor ~10 on the matrix elements i.e. a factor ~100 on the lifetime Phase Space Integral Exactly Calculable Calculated values span a range of 3-4 orders of magnitude around the experimental value Tretyak and Zdesenko 2002

12. The interesting ones   decay rate scales with Q 5  2  decay rate scales with Q 11 Q-value (keV) IsotopeNat. abund. (%) Ca 484271 0.187 Ge 7620397.8 Se 8229959.2 Zr 9633502.8 Mo 10030349.6 Pd 110201311.8 Cd 11628097.5 Sn 12422885.64 Te 130252934.5 Xe 13624798.9 Nd 15033675.6 Experiments ELEGANT, CANDLES GERDA, MAJORANA NEMO-3 NEMO-3, MOON COBRA, CAMEO CUORICINO, COBRA EXO, XMASS ZORRO DCBA

13. Nuclear matrix elements To be sure: A factor 3 uncertainty in the NME means about factor of 10 in half-life P. Vogel, PDG 02

14.  +  + - modes (A,Z)  (A,Z-2) + 2 e + (+2 e )  +  + e - + (A,Z)  (A,Z-2) + e + (+2 e )  +/EC 2 e - + (A,Z)  (A,Z-2) (+2 e ) EC/EC Important to reveal mechanism if 0  is discovered Enhanced sensitivity to right handed weak currents (V+A) n n p p e e In general: Q-4m e c 2 Q-2m e c 2 Q Double charged higgs bosons, R-parity violating SUSY couplings, leptoquarks...

15. Neutrino mass vs. right handed currents (eV) Possible evidence M. Hirsch et al., Z. Phys. A 347,151 (1994) EC/ß + 106 Cd: COBRA, TGV

16. Why are we here? 1 / T 1/2 = PS * ME 2 * (m / m e ) 2 0+0+ 1+1+ (A,Z) (A,Z+1) (A,Z+2) 0+0+ charge exchange muon capture beta decays antineutrino- capture nu N scattering Theory: Shopping list what to measure to improve calculations Experiment: Where can it be measured, who? „Ultimate dream“: coherent effort, strategy paper to get things done Q - values