bb decay:Present and Future
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decay:Present and Future
Ruben SaakyanUCL
8 November 2004Manchester University
Particle Physics seminar
PREVIEW Motivation Present status
Status of “evidence” Future projects UK in NEMO/SuperNEMO
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Motivation
e
Ue1 Ue2 Ue3U1 U2 U3U1 U2 U3
123
U 0.5 0.87 0 0.61 0.35 0.710.61 0.35 0.71
Neutrino Mixing Observed !
From KamLAND, solar and atmospheric
VERY approximately
m2LMA ≈ 5×10-5 eV2 = (7 meV)2
m2atm ≈ 2.5×10-3 eV2 = (50 meV)2
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Neutrino MASSWhat do we want to know?
or
• Relative mass scale (-osc)
• Mass hierarchy (-osc and )
• Absolute mass scale ()
Dirac or Majorana
1 3e
Ue12 Ue2
2 Ue32
MixingOnly from From -osc
<m> ~ 0 - 0.01 eV <m> ~ 0.02 - 0.06 eV
preferred bytheorists(see-saw)
degenerate: <m> > 0.1 eV
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Decay Basics
2+
0+
0+
0+
2-
Ge76
As76
Se76
In many even-even nuclei, decay is energetically forbidden. This leaves
as the allowed decay mode.
Q Endpoint
Energy
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Double beta decay and neutrino mass
1 22 2 21/ 2 0(0 0 ) ( , )T G E Z M
1 20 0 0 21/ 2 0(0 0 ) ( , )T G E Z M m
L=0
L=2 !
Q
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Effective Majorana Mass(inverted hierarchy case)
2 222 2 i
N N
ei i ei ii i
m U m U e m
Ue12 m1
Ue22 m2
Ue32 m3
<mee>
min
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Isotopes Best candidates:
76Ge, Q2.038 MeV 48Ca, Q 4.272 MeV 82Se, Q 2.995 MeV 100Mo, Q 3.034 MeV 116Cd, Q 2.804 MeV 130Te, Q 2. 528 MeV 136Xe, Q 2.48 MeV 150Nd, Q 3.368 MeV
High Q is important (G0 ~ Q5, G2 ~ Q
11) In most cases enrichment is a must Different isotopes must be investigated due to
uncertainties in NME calculations !
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The Experimental Problem( Maximize Rate/Minimize Background)
Natural Activity:
(238U, 232Th) ~ 1010 yearsTarget: (0) > 1025 years
DetectorShielding
Cryostat, or other experimental supportFront End Electronics
etc.+
Cosmic ray induced activity
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A History Plot
<m> < 0.35 – 0.9 eV
mscale ~ 0.05 eV from oscillation experiments
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Hieldeberg-Moscow (Gran Sasso)(Spokesperson: E. Klapdor-Kleingrothaus, MPI)
<m> = 0.4 eV ???
• 5 HPGe 11 kg, 86% 76Ge• E/E 0.2%• >10 yr of data taking
<m> < 0.3 – 0.7 eV If combine HM and IGEX
First claim (end 2001)
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Heidelberg claim. Recent developments
hep-ph/0403018, NIMA, Phys. Rev…Data analysed for 1990 – 2003
71.7 kgyr
• Data reanalyzed with improved binning/summing • Peak visible• Effect reclaimed with 4.2• <m> = (0.2 – 0.6) eV, 0.4 eV best fit<m> = (0.1 – 0.9) eV (due to NME)
• Looks more like 2.5 of effect•214Bi line intensities do not match
214Bi 214Bi
unkn
own
Personal view
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CUORICINO (bolometer)
NEMO-3(Tracking calorimeter)
These two will be determining fate until ~2007-2008Sensitivity ~ 0.2 eV
Current Experiments
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Located in LNGS, Hall A
Cuoricino (Hall A)
CUORE R&D (Hall C)
CUORE (Hall A)
Today:CUORICINO
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Incident particle
absorber crystal
heat bath
Thermal sensor
Today: CUORICINO2 modules, 9 detector each,crystal dimension 3x3x6 cm3
crystal mass 330 g9 x 2 x 0.33 = 5.94 kg of TeO2
11 modules, 4 detector each,crystal dimension 5x5x5 cm3
crystal mass 790 g4 x 11 x 0.79 = 34.76 kg of TeO2
40.7kg total
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Today:CUORICINO
• Operation started early 2003• BG = 0.19 counts/kev/kg/y• E/E = 4 eV @ 2 MeV
Neutrino 2004:m < 0.3 – 1.6 eV (all NME)
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AUGUST 2001
Today: NEMO-III
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100Mo 6.914 kg Q= 3034 keV
decay isotopes in NEMO-3 detector
82Se 0.932 kg Q= 2995 keV
116Cd 405 g Q= 2805 keV
96Zr 9.4 g Q= 3350 keV
150Nd 37.0 g Q= 3367 keV
Cu 621 g
48Ca 7.0 g Q= 4272 keV
natTe 491 g
130Te 454 g Q= 2529 keV
measurement
External bkg measurement
search (All the enriched isotopes produced in Russia)
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Drift distance
100Mo foil100Mo foil
Transverse view Longitudinal view
Run Number: 2040Event Number: 9732Date: 2003-03-20
Geiger plasmalongitudinalpropagation
Scintillator + PMT
Deposited energy: E1+E2= 2088 keVInternal hypothesis: (t)mes –(t)theo = 0.22 nsCommon vertex: (vertex) = 2.1 mm
Vertexemission
(vertex)// = 5.7 mm
Vertexemission
Transverse view Longitudinal view
Run Number: 2040Event Number: 9732Date: 2003-03-20
Criteria to select events:• 2 tracks with charge < 0• 2 PMT, each > 200 keV• PMT-Track association • Common vertex
• Internal hypothesis (external event rejection)• No other isolated PMT ( rejection)• No delayed track (214Bi rejection)
events selection in NEMO-3 Typical 2 event observed from 100Mo
Trigger: 1 PMT > 150 keV 3 Geiger hits (2 neighbour layers + 1) Trigger rate = 7 Hz events: 1 event every 1.5 minutes
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(Data 14 Feb. 2003 – 22 Mar. 2004)
T1/2 = 7.72 0.02 (stat) 0.54 (syst) 1018 y
100Mo 22 preliminary results
4.57 kg.y
Cos()
Angular Distribution
Background subtracted
22 Monte Carlo
• Data
145 245 events6914 g
241.5 daysS/B = 45.8
NEMO-3
100Mo
E1 + E2 (keV)
Sum Energy Spectrum
145 245 events6914 g
241.5 daysS/B = 45.8
NEMO-3
100Mo
• Data
Background subtracted
22 Monte Carlo
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Simkovic, J. Phys. G, 27, 2233, 2001
Single electron spectrum different between SSD and HSD
100Mo 22 Single Energy Distribution
22 HSDMonte Carlo HSD
higher levels Background subtracted
• Data 22 SSD Monte Carlo Background subtracted
• Data
SSDSingle State
HSD: T1/2 = 8.61 0.02 (stat) 0.60 (syst) 1018 y
SSD: T1/2 = 7.72 0.02 (stat) 0.54 (syst) 1018 y
100Mo 22 single energy distribution in favour of Single State Dominant (SSD) decay
4.57 kg.yE1 + E2 > 2 MeV
4.57 kg.yE1 + E2 > 2 MeV
HSD, higher levels contribute to the decay
SSD, 1 level dominates in the decay (Abad et al., 1984, Ann. Fis. A 80, 9)
100Mo
0
100Tc1
/ndf = 139. / 36 /ndf = 40.7 / 36
NEMO-3 NEMO-3
Esingle (keV) Esingle (keV)
Esingle (keV)
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Today:NEMO-III
Present 90%CL limits from NEMO-III(216.4 days) 82Se:T1/2() > 1.9 1023 y, m < 1.3 – 3.6 eV
Simkovic et al., Phys. Rev. C60 (1999) Stoica, Klapdor, Nucl. Phys. A694 (2001) Caurier et al., Phys. Rev. Lett. 77 1954 (1996)
100Mo T1/2() > 3.5 1023 y, m < 0.7 – 1.2 eV Simkovic et al., Phys. Rev. C60 (1999) Stoica, Klapdor, Nucl. Phys. A694 (2001)
Expected Reach in 5 years after RadonPurification 100Mo T1/2() > 4.0 1024 y, m < 0.2 – 0.35 eV 82Se:T1/2() > 8.0 1023 y,,m < 0.65 – 1.8 eV
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Strategy for future.An Ideal Experiment
Large Mass (0.1t) Good source radiopurity
Demonstrated technology Natural isotope
Small volume, source = detector Tracking capabilities
Good energy resolution or/and Particle ID Ease of operation
Large Q value, fast (0) Slow (2) rate Identify daughter
Event reconstruction Nuclear theory
01
041
BGMt
m
BGMt
Ebm
live
live
All requirements can NOT be satisfied Red – must be satisfied
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A Great Number of Proposals(Some may start taking data in 2009-2010)
DCBA Nd-150 20 kg Nd layers between tracking chambers
SuperNEMO Se-82, Various 100 kg of Se-82(or other) foil
COBRA CAMEO
Te-130,Cd-116Cd-116
CdTe semiconductors1 t CdWO4 crystals
CANDLES Ca-48 Several tons CaF2 crystals in liquid scint.
CUORE Te-130 750 kg TeO2 bolometers
EXO Xe-136 1 ton Xe TPC (gas or liquid)
GEM Ge-76 1 ton Ge diodes in liquid nitrogen
GERDA Ge-76 0.5-1 ton Ge diodes in LN2/LAr
GSO Gd-160 2 t Gd2SiO5:Ce crystal scint. in liquid scint.
Majorana Ge-76 500 kg Ge diodes
MOON Mo-100 Mo sheets between plastic scint., or liq. scint.
Xe Xe-136 1.56 t of Xe in liq. Scint.
XMASS Xe-136 10 t of liquid Xe
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GERDA. 76Ge Phase I: collect 76Ge detectors
from HM(11kg)+IGEX(8kg) [email protected] c/keV/kg/y
sens-ty: 3·1025 y, 0.24-0.77 eV Confirm Klapdor with 5 OR rule out at 98%
Phase II:enlarge to ~35-40 kg BG < 10-3 c/keV/kg/y within 4 yr ~ 100 kgy 2·1026 y, 0.09-0.29 eV
Phase III: 0.5 -1 ton Possible merge with Majorana ~ 0.03 eV
“Naked” 76Ge detectors in LN2/LArOriginal idea from GENIUS (Klapdor)
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Cryogenic Underground Observatory for Rare Events - CUORE
BerkeleyFirenzeGran SassoInsubria (COMO) LeidenMilanoNeuchatelU. of South CarolinaZaragoza
SpokespersonEttore Fiorini
Milano
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CUORE
CUORICINO×20 270 kg 130Te(~ 750 kg natTe)
0.001 / / /200
CUORICINOBG c keV y kg
Compact: 70×70×70 cm3
5 yr in Gran Sasso: <m> ~ 0.04 eV
APPROVED !
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The Majorana ProjectDuke U.North Carolina State U.TUNLArgonne Nat. Lab.JINR, DubnaITEP, MoscowNew Mexico State U.Pacific Northwest Nat. Lab.U. of WashingtonLANLLLNLU. of South CarolinaBrownUniv. of ChicagoRCNP, Osaka Univ.Univ. of Tenn.
Co-SpokespersonsFrank Avignone
Harry Miley
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Majorana 0.5 ton of 86% enriched
76Ge Very well known and
successful technology Segmented detectors using
pulse shape discrimination to improve background rejection.
Prototype ready to go this autumn/winter. (14 crystals, 1 enriched)
100% efficient Can do excited state decay.
5 yr in a US undegr lab<m> ~ 0.03 eV
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Enriched Xenon Observatory - EXO
U. of AlabamaCaltechIBM AlmadenITEP MoscowU. of NeuchatelINFN PadovaSLACStanford U.U. of TorinoU. of TriesteWIPP Carlsbad
SpokespersonGiorgio Gratta
Stanford
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EXO 10 ton, ~70% enriched 136Xe 70% effic., ~10 atm gas TPC
or LXe chamber Optical identification of Ba
ion. Drift ion in gas to laser path or extract on cold probe to
trap. 200-kg enrXe prototype (no
Ba ID) being built Isotope in hand 5 yr in a US underground lab
<m> ~ 0.05 eV
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Cadmium-Telluride O-neutrino double-Beta Research ApparatusCOBRA
SussexOxfordDortmundWarwick
Project LeaderKai Zuber
Sussex
• CdTe or CdZnTe semiconductor detectors• Good E/E• Two isotopes 116Cd and 130Te• Operate at room temperature• New approach
• Large R&D programme needed• If successful can get to ~10-20 meV in ~ 20yr
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SuperNEMO
UCLManchesterICLAL, OrsayBordeauxStrasbourgPragueITEP (Moscow)JINR (Dubna)Saga Univ. (Japan)INEEL (USA)MHC (USA)
• NEMO3 x 10 + better E/E• robust and developed technology• quick start (100 kg of isotope)
F ~ (E/E)6
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Isotopes in SuperNEMO
Isotope Q, MeV
100Mo 3.033
82Se 2.995
116Cd 2.802
130Te 2.529
2 821/ 22 100
1/ 2
( )~ 10
( )T Se
T Mo
Factor of 10 lower BG for 82Se
Can be produced in centrifuge - $30K-$50K/kg
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SuperNEMO
4 supermodulesPlanar geometry
100 kg 82Se (Q = 3 MeV, large T1/2
2
Sensitivity ~0.04 eV in 5 yrFeasible if Zero BG experiment:
1) No BG from radioactivity the only possible BG from 2 tail (NEMO-III)2) Improve E/E from existing (14%-16%)/E to (8%-10%)/E Demonstrated (UCL+ Dubna)
Boulby mine is an attractive experimental site
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SuperNEMO. Time Scale 2004 – 2005 scintillator R&D
Attempt to reach 5-6% 2005-2006: Design study
proposal (PPRP, Dec-Feb) Prototype submodule in
Boulby 2007-20010: Production 2009-2010: Start taking data 2014: planned sensitivity
~0.04 eV Excellent chance to be the
first to reach 40-50 meV
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Concluding Remarks
Very exciting time for neutrino physics in general and 0 in particular
From oscillations: positive signal is a serious possibility
“Good value”: ~$50M for the great potential scientific gain
Several experiments with different isotopes are needed (recall NME uncertainties)