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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
Motivation
e
Ue1 Ue2 Ue3
U1 U2 U3
U1 U2 U3
1
2
3
U 0.5 0.87 0
0.61 0.35 0.71
0.61 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
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
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
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
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
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 !
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
A History Plot
<m> < 0.35 – 0.9 eV
mscale ~ 0.05 eV from oscillation experiments
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)
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
214Bi214Bi
unkn
own
Personal view
CUORICINO (bolometer)
NEMO-3(Tracking calorimeter)
These two will be determining fate until ~2007-2008Sensitivity ~ 0.2 eV
Current Experiments
Located in LNGS, Hall A
Cuoricino (Hall A)
CUORE R&D (Hall C)
CUORE (Hall A)
Today:CUORICINO
Incident particle
absorber crystal
heat bath
Thermal sensor
Today: CUORICINO
2 modules, 9 detector each,crystal dimension 3x3x6 cm3
crystal mass 330 g
9 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
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)
AUGUST 2001
Today: NEMO-III
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)
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
(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
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
• Data22 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
100Tc
1
/ndf = 139. / 36 /ndf = 40.7 / 36
NEMO-3 NEMO-3
Esingle (keV) Esingle (keV)
Esingle (keV)
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
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
04
1
BGMt
m
BGMt
Ebm
live
live
All requirements can NOT be satisfied Red – must be satisfied
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-116
Cd-116
CdTe semiconductors
1 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
GERDA. 76Ge
Phase I: collect 76Ge detectors from HM(11kg)+IGEX(8kg) 15kgy+BG@0.01 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)
Cryogenic Underground Observatory for Rare Events - CUORE
Berkeley
Firenze
Gran Sasso
Insubria (COMO)
Leiden
Milano
Neuchatel
U. of South Carolina
Zaragoza
SpokespersonEttore Fiorini
Milano
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 !
The Majorana ProjectDuke U.
North Carolina State U.
TUNL
Argonne Nat. Lab.
JINR, Dubna
ITEP, Moscow
New Mexico State U.
Pacific Northwest Nat. Lab.
U. of Washington
LANL
LLNL
U. of South Carolina
Brown
Univ. of Chicago
RCNP, Osaka Univ.
Univ. of Tenn.
Co-SpokespersonsFrank Avignone
Harry Miley
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
Enriched Xenon Observatory - EXO
U. of AlabamaCaltechIBM AlmadenITEP MoscowU. of NeuchatelINFN PadovaSLACStanford U.U. of TorinoU. of TriesteWIPP Carlsbad
SpokespersonGiorgio Gratta
Stanford
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
Cadmium-Telluride O-neutrino double-Beta Research ApparatusCOBRA
Sussex
Oxford
Dortmund
Warwick
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
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
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
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
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
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)
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