1. Double beta decay, neutrino physics and something else
The birth of double beta decay
From low energy nuclear physics to neutrino mass and properties
The physics of rare events
Experimental approaches and difficulties
Present experimental status
The future
The nightmare of nuclear matrix elements
Something else
Conclusions
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Ettore Fiorini

2. Benasque March 19,2015
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3. Double beta decays 1935 M.Goeppert-Mayer, P.R. 48 (1935) 512 T>1020
Majorana, Nuovo Cimento 14 (1937) 171
Symmetric Theory of Electron and Positron
G. Racah, Nuovo Cimento 14 (1937) 322
W.H. Furry Lepton number nonconservation
1967: 130Te, Geochemical Ogata and Takaoka,
Kirsten et
1987: 82Se, Direct counting Moe et al .
1987 : Source=detector 48Ca, 76Ge
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4. (A,Z) => (A,Z+2) + 2 e- + 2 ne
Two neutrino double beta decay Allowed by the standard model
Found in eleven nuclei ( 130Xe is new!) to ground state and in two to excited state
(A,Z) => (A,Z+2) + 2 e- + c ( …2,3 c) Emission of a massless Goldston boson named Majoron (Gelmini and Roncadelli)
3. (A,Z) => (A,Z+2) + 2 e-
Neutrinoless double beta decay. The two electrons share the total transition energy E1 + E2 => DE => a peak should appear in the sum spectrum of the two electrons
Other possible “DL=2” decays - Double positron decay => b+ b+ - Positron decay + Electron Capture => EC- b+ - Double electron capture => EC-EC
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5. Two neutrino and neutrinoless double beta decay
Measurement of the CP phase in the 0n bb-decay
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7. How to search for bb decay
Geochemical experiments 82Se = > 82Kr, 96Zr = > 96Mo, 128Te = > 128Xe , 130Te = > 130Te Radiochemical experiments 238U = > 238Pu (non confirmed) e-
Direct experiments
Source  detectors
Source = detector
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8. Many types of detectors
Experimental challenges
Many types of detectors
Cloud chambers
Emulsions?
Bubble chambers ? (yes for Dark Matter)
Scintillators
Double state liquids
Time projectrion chambers
Tracking and imagining devices
Single atom counters 136Xe => 136Ba
Bolometers
Hybrid devices
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9. A first source = detector bb experiment
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10. RARE events One of the main problem => background
Cosmic rays => underground physics
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11. Where to go ?
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12. Benasque March 19,2015
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13. Benasque March 19,2015
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14. The Jin Ping Laboratory (700 m.w.e)
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15. Benasque March 19,2015
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16. Radioactivity
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17. Benasque March 19,2015
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18. The second mystery of Ettore Majorana
ne ne
In 1937, Majorana [2] theoretically showed that the conclusions of
the theory of β decay remain unchanged under the assumption of the existence of only one type of the neutrino having no antiparticle
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19. : Dirac or Majorana neutrino? → → <= => Majorana =>1937
RIGHT
LEFT :
→ → <= =>
Majorana =>1937
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20. Benasque March 19,2015
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21. EXO-200 => T2n1/2 2. 71±0. 017(stat. )±0. 06(sys. )×1021 yr
EXO-200 => T2n1/ ±0.017(stat.)±0.06(sys.)×1021 yr. Kamland-Zen ± 0.02(stat) ± 0.14(syst) × 1021 yr GERDA I (stat) × 1021 yr
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22. Neutrino oscillations Sterile neutrinos
LSND,Miniboon,Gallex,reactors
Great discovery requires great evidence (P. de Bernardis)
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25. Benasque March 19,2015
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26. Bracking news then 0 in 76Ge
<mn> ~ 0.34eV
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27. GERDA
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28. Complain by H.Klapdor
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29. Future experiments on DBD
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30. GERDA Majorana Supernemo
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31. Benasque March 19,2015
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32. Benasque March 19,2015
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33. SNO+
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34. Benasque March 19,2015
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35. NEXT
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36. Energy resolution <1 eV ~ 1eV @ 6 keV
Thermal detectors
Thermal sensor
absorber
crystal
Incident particle
Energy resolution <1 eV ~ 1eV @ 6 keV
~10 eV ~keV @ 2 MeV
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37. Benasque March 19,2015
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38. CUORICINO
CUORE0
CUORE
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39. Heat+ scintillation , light, Cherenkov light
Hybrid techniques
Heat+ scintillation , light, Cherenkov light
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40. 0νββ emitters: 130Te, 82Se, 100Mo & few others
Crystals: TeO2 , ZnSe, ZnMoO4, CaMoO4
Operation at <20 mK:
Heat sink
Thermometer
Crystal made
from
ββ-isotopes
Cuore
(w/o light detection)
Lucifer, Lumineu, Amore
(with light detection)
Light detector
Lucifer
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41. 9/15 kg 82Se delivered final batch for 02/2015
Qββ (82Se) = 2995 keV
Array of enr. (95%) Zn82Se crystals
Total 82Se nuclei: ( ) 1025
Single detector: 460 g
BI (goal): 1-2 x10-3 cts / (keV kg yr)
ΔE (FWHM): keV
Bgd (internal α’s):
17.2±4.6 μBq/kg (232Th)
24.6±5.5 μBq/kg (238U)
Isotope delivery:
9/15 kg 82Se delivered final batch for 02/2015
Crystal growth:
Schedule for Jan - June 2015
Current yield: 70%
‘anomalous
β/γ-quenching’
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42. Now a competitor AMORE Advanced Mo based Rare process Experiment
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43. The nightmare of matrix elements Francesco Jachello entering the field
Before the nightmare
Francesco Jachello entering the field
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44. Robertson idea
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45. Benasque March 19,2015
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46. Is Francesco Iachello right ? Amicus Plato, sed magis amica veritas
Plato is a friend , but truth even a better one
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47. Majorana neutrino and consequences
Detectors of unprecedentent sensitivity
Environmental radioactivity
Trace elements
Archaeometry
Reactors => friends and enemies
Is neutrinoless double beta decay the only way to test lepton conservation?
A possible experiment to search
ne => n
A favor to be returned => reactor physics
=> Measurement of the position of the fire inside the reactor
=> Displacement of the Uranium column in the core
Benasque March 19,2015
Ettore Fiorini

48. The Fukushima accident.
Agreement by bb groups =>Measurements of air contamination in Osaka, Berkeley, Seattle etc. Only partially related to the distance
Detection of air contamination a factor of million less in Milan with respect to Fukushima
Radionuclide
Origin
Gamma Peak (keV)
Branching ratios (%)
Absolute detection efficiency εabs (%)
Min (μ Bqm−3)
Max (μ Bqm−3)
Mean (μ Bqm−3)
7Be
Cosmogenic
477
10.3
0.69 ± 0.10
200 ± 40
970 ± 190
470 ± 90
131I
Fukushima
284
81.2
1.08 ± 0.16
23 ± 4
410 ± 82
82 ± 16
364
60.6
0.88 ± 0.13
134Cs
604
97.6
0.57 ± 0.09
1.3 ± 0.3
80 ± 16
9.2 ± 1.8
796
85.4
0.47 ± 0.07
136Cs
818
100
0.46 ± 0.07
0.005 ± 0.001
137Cs
661
84.6
0.54 ± 0.08
1.6 ± 0.3
93 ± 19
10 ± 2
Benasque March 19,2015
Ettore Fiorini

49. Majorana theory for electron and positron
Application to neutrino => can a ½ spin particle be its own antiparticle?
In superconductors Cooper pairs, being boson like particles, form condensates. Cooper pairs can be added to semiconductors with hole producing spin ½ exitons.
Superconductors can contain magnetic wires acting as quasiparticles
Can the Majorana rule be applied to these quasiparticles?
Benasque March 19,2015
Ettore Fiorini

50. Conclusions
Massive detectors (now expensive) of unique sophistication The reduction of the background which could hide neutrinoless bb events has reached an unprecedented sensistivity The quenching due to the new value assummed for gA could reduce the expecttion of the neutrino mass limit by a factor 4 to 5. If true it strongly reduces our hope to reach the invers hierarchy region The validity to extend to neutrinoles DBD the gA obtained from two neutrino and single beta decay should be justified The sophistication reached and to be reached in serches for DBD could have appplications in other fields of science Aplication to solid state physics of the Maiorana theory could bring to results as important as in elementary particle physics
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Ettore Fiorini

51. There are more things in Earth and Heaven , Polonius, that can be dreamt of by your Philosophy Hamlet
Benasque March 19,2015
Ettore Fiorini