Transcript Search for Neutrinoless Double Beta Decay with NEMO 3
Search for neutrinoless double beta decay with NEMO 3 and SuperNEMO experiments Vladimir Vasiliev UCL, London, UK on behalf of the NEMO collaboration
SUSY 2007
Karlsruhe, 28 July 2007
bb
decay,
n
mass mechanism
predicted in 1935 by Maria Goeppert-Mayer 1-5 July 2007, ILIAS meeting, Blaubeuren D L = 2 - only possible for Majorana neutrinos with mass > 0 Beyond the SM: Lepton Number Violation !
Vladimir Vasiliev NEMO 3/ SuperNEMO status 2
bb
decay and SUSY: R-parity breaking
L
'
ijk LQD
d R +d R → u L +u L +e L +e L exchange with: squarks neutralinos gluinos
related to (
' 111
)
2 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 3
bb
decay and SUSY: squark mixing
L
'
ijk LQD
d R +d R → u L +u L +e L +e L Mixing between L and R- handed fermion superpartners.
Paes, Hirsch,Klapdor-Kleingrothaus, PLB 459(1999) 450
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 4
bb
decay and SUSY: neutrino mass
L
'
ijk LQD
d R +d R → u L +u L +e L +e L neutrino acquires mass due to SUSY radiactive corrections
Gozdz, Kaminski, Šimkovic, PRD 70 (2004) 095005
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 5
bb
decay mechanism
If observed,
how to determine mechanism
: n
mass, SUSY, V+A ... ???
• measure kinematical parameters: angular correlation, individual electron energy!
• measure several isotopes! • measure bb0n decay to excited state of final nuclei!
Calorimetry plus tracking approach: Detection of both electrons, three kinematic observables: energies; angular correlation; energy sum individual electron Sources separated from the detector: Particle identification: measure T ½ for several isotopes e ,
g
; good signature for decay to excited states Unique and complementary
6 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status
key techniques: tracking, calorimetry, timing
Goal: reconstruct 2 electrons of the final state
E1 + E2 = Q bb Particle physics - like approach:
Measure several observables of the final state
Trajectories of 2 electrons Energies of 2 electrons Time Magnetic field curvature ("+" vs "-")
Reconstruct the final state topology and kinematics Several requirements for candidate events
Topology (vertex, track-scintillator correlation)
Time coincidence 2-electron invariant mass Identify e , e + ,
g, a
Able to measure backgrounds 20 sectors NEMO-3 B (25 G)
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 7
Multi source detector
100 Mo 6.914 kg
Q bb = 3034 keV
82 Se 0.932 kg
Q bb = 2995 keV bb0n
search
1-5 July 2007, ILIAS meeting, Blaubeuren bb2n
measurement 116 Cd 405 g
Q bb = 2805 keV
96 Zr 9.4 g
Q bb = 3350 keV
150 Nd 37.0 g
Q bb = 3367 keV
48 Ca 7.0 g
Q bb = 4272 keV
130 Te 454 g
Q bb = 2529 keV
nat Te 893 g Cu 621 g
Vladimir Vasiliev NEMO 3/ SuperNEMO status
Detector bkg measurement
8
Sector interior view
PMTs scintillators
bb
isotope foils
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status
cathode rings wire chamber Calibration tube
9
Installation in Modane
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 10
Installation in Modane
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 11
With shielding
wood coil iron shield
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status
water tank
12
Full detector now
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 13
Typical
bb2n
event observed from
100
Mo
Transverse view Run Number: 2040 Event Number: 9732 Date: 2003-03-20 Vertex emission Longitudinal view Vertex emission Deposited energy:
E 1 +E 2 = 2088 keV
Internal hypothesis:
(
D
t) mes –(
D
t) theo = 0.22 ns
Common vertex:
(
D
vertex)
= 2.1 mm Criteria to select
bb • 2 tracks with charge < 0 • 2 PMT, each > 200 keV • PMT-Track association • Common vertex
events: 100 (
D
vertex) // = 5.7 mm Mo 6.914 kg
Q bb = 3034 keV • Internal hypothesis TOF (external event rejection) • No other isolated PMT ( g • No delayed a track ( 214 rejection) Bi rejection) 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 14
NEMO backgrounds
•Natural radioactivity: • U/Th chain •
40
K • Rn •cosmic
m
•neutrons
External Internal double Compton b + Compton Compton + Moller b + Moller pair production b + IC 15 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status
Backgrounds: Radon purification facility
Running since Oct. 4th, 2004 in FréjusUnderground Lab.
1 ton charcoal @ -50 o C, 7 bars
Flux: 150 m 3 /h Activity of 222 Rn : Before Facility = 15 Bq/m 3 After Facility < 15 mBq/m 3
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 16
Radon purification facility, effect inside NEMO3
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 17
Backgrounds:
bb
-like events from Cu
- background sources simulated using Monte Carlo - radioactivity rates from material tests in HPGe and control channel meas's Phase II data; ~ 1.5 y.
MC prediction: 130 ev.
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 18
NEMO 3 highlights: 2
b
2
n
100
Mo
12000 10000 Sum energy spectrum
NEMO-3
100 Mo
219 000 events 6914 g 389 days S/B = 40 8000 6000 4000
•
Data 2
b
2
n
Monte Carlo Background subtracted 2000 0 12000 10000 8000 6000 4000 2000
100
Angular distribution
NEMO-3
Mo
219 000 events 6914 g 389 days S/B = 40
•
Data 2
b
2
n
Monte Carlo Background subtracted 0 E 1 + E 2 (MeV) T 1/2 (
bb2n
) = 7.11
0.02 (stat)
0.54 (syst)
10 18 years
Phys. Rev. Lett. 95 182302 (2005)
« bb factory» → tool for precision test
Cos(
)
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 19
NEMO 3 highlights: 2
b
2
n
preliminary
82 Se
932 g 389 days 2750 events S/B = 4 Preliminary results for ~360 d Phase I data. Additional statistics is being analysed and to be published soon.
82 Se T 1/2 = 9.6 ± 0.3 (stat) ± 1.0 (syst)
10 19 y 116 Cd T 1/2 = 2.8 ± 0.1 (stat) ± 0.3 (syst)
10 19 y 150 Nd T 1/2 = 9.7 ± 0.7 (stat) ± 1.0 (syst)
10 18 y 96 Zr T 1/2 = 2.0 ± 0.3 (stat) ± 0.2 (syst)
10 19 y 48 Ca T 1/2 = 3.9 ± 0.7 (stat) ± 0.6 (syst)
10 19 y 48 Ca
1-5 July 2007, ILIAS meeting, Blaubeuren
Background subtracted
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NEW in 2007: direct meas. of
130
Te 2
b
2
n The bb2n half-life of 130 Te has been a long-standing mystery:: Geochemical: - (25 ± - (27 ± - (7.9 ± 2) x 10 20 2) x 10 20 1) x 10 20 years (Kirsten 83) years (Bernatowicz 93) years (Takaoka 96) - ~8 x 10 20 years (Manuel 91) Difference between ‘old’ and ‘young’ ores due to time dependence of constants..?
Ratio of 82 Se/ 130 Te (less systematics): -(9 ± 1) x 10 20 years (average by A. Barabash) Direct measurement: -(6.1 ± 1.4 (syst) ± 2.9
3.4
) x 10 20 years (Arnaboldi 2003) 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 21
NEW in 2007: direct meas. of 130Te 2b2n
109 events 607 events 534 days, 454 g of 130 Te 1-5 July 2007, ILIAS meeting, Blaubeuren background subtracted Vladimir Vasiliev NEMO 3/ SuperNEMO status 22
NEMO 3 highlights: 2
b
0
n
100
Mo &
82
Se
100 Mo, Phase I + II, 693 days 82 Se , Phase I + II, 693 days
T 1/2
bb0n
> 5.8 x 10 23 (90 % CL) T 1/2
bb0n
> 2.1 x 10 23 (90 % CL)
n
>* < 0.8 – 1.3 eV
' 111 < 1.5 10 -4 expected in 2009: T 1/2
bb0n
> 2 x 10 24 (90 % CL) T 1/2
bb0n n
' >* < 1.4-2.2 eV 111 < 2.5 10 > 8 x 10 23 -4 (90 % CL)
n
>* < 0.4 – 0.7 eV
n
>* < 0.7-1.1 eV
Collaboration decided to perform blind analysis with mock data
Plan to open the box and update the results ~ summer 2008 and again ~ early 2010.
1-5 July 2007, ILIAS meeting, Blaubeuren *
Recent QRPA NME calculation as in MEDEX'07
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'Majoron' search
Axions (‘Majorons’) with coupling to neutrinos 1-5 July 2007, ILIAS meeting, Blaubeuren Mo Se best limits n=1 ** n=2 ** n=3 ** n=7 **
>2.7∙10 22
g ee <(0.4 1.8)∙10 -4
>1.5∙10 22
g ee <(0.7 1.9)∙10 -4
>1.7∙10 22 >6.0∙10 21 >1.0∙10 22 >7∙10 19 >3.1∙10 21 >5.0∙10 2 0
n: spectral index, limits on half-life in years ** PI data ,
R.Arnold et al. Nucl. Phys. A765 (2006) 483
Vladimir Vasiliev NEMO 3/ SuperNEMO status 24
SuperNEMO project
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 25
~ 60 physicists, 27 laboratories , 12 countries , USA MHC INL (U Texas) Marocco Fes U UK UC London U Manchester Imperial College Spain U Valencia U Zaragoza U Barcelona France CEN Bordeaux IReS Strasbourg LAL Orsay LPC Caen LSCE Gif/Yvette Finland U Jyvaskula Poland U Warsaw Russia JINR Dubna ITEP Mosow Kurchatov Institute Ukraine INR Kiev ISMA Kharkov Slovakia (U. Bratislava) Czech Republic Charles U Praha IEAP Praha Japan U Saga KEK U Osaka
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 26
Very preliminary SuperNEMO design
Planar and modular design: ~ 100 kg of isotope (~20 modules
5-7 kg) 1 module: Source (~40 mg/cm 2 ) 4 (length) x 3(height) m 2 Tracking : drift chamber ~3000 cells in Geiger mode Calorimeter: scintillators + PM ~1 000 PM if scint. blocks ~ 100 PM if scint. bars
Top view 1 m 5 m 5 m 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 27
Very preliminary SuperNEMO design
Single sub-module with ~7 kg of isotope 5 m 1-5 July 2007, ILIAS meeting, Blaubeuren ~20 sub-modules for 100+ kg of isotope surrounded by shielding Vladimir Vasiliev NEMO 3/ SuperNEMO status 28
SuperNEMO design study
February 2006 – January 2009
• Approved in UK, France and Spain. Similar proposals under consideration in Russia, Czech Republic, Japan • Main tasks and deliverables
– R&D on critical components • Calorimeter energy resolution of 4% at 3 MeV • Optimisation of tracking detector and construction (robot) • Better background rejection (e.g. extra veto counters) • Ultrapure source production and purity control • Simulations and geometry optimisation – Technical Design report – Experimental site selection (Frejus, Canfranc, Gran Sasso, Boulby) 5 m 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 29
R&D: SuperNEMO calorimeter
• Goal: FWHM • Studies
7%/
E
4% at 3 MeV (Currently 14-16%/
E in NEMO3) • A combination of energy losses in the foil and calorimeter DE/E
– – – – –
Organic (plastic or liquid), Shape, size, coating PMTs (Photonis, Hamamatsu, ETL) Light guides, optical contact Chemistry High QE Hamamatsu tube + See Jean-Stephane's talk for details
Vladimir Vasiliev NEMO 3/ SuperNEMO status
= BC404 scintillator wraped in teflon
D E/E = 6.5% at 1 MeV 3.8% at 3 MeV if 1/ E 30 1-5 July 2007, ILIAS meeting, Blaubeuren
R&D: tracker optimisation
optimize: wire length and diameter wire material and diameter, read-out, gas mixture etc 9-cell prototype built 90 cell prototype + 300 cell prototype to be built by Spring 2008 About 500k wires to be strung, crimped, terminated => wire robot under development 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 31
R&D : radio purity and BiPo device
Need to measure radio purity at a few m Bq/kg level Beyond sensitivity of conventional Ge detectors Build new tool, BiPo detector.
238 U Bi-Po Process 214 Bi
(19.9 mn) b
214 Po
(
164
m
s
) a 210 Pb 22.3 y 210 Tl (1.3 mn)
232 Th 212 Bi
(60.5 mn) b
212 Po
(
300 ns
) a 208 Pb (stable)
208 Tl
(3.1 mn) 1-5 July 2007, ILIAS meeting, Blaubeuren
e
-
prompt e
a
delay e
a
Delay
a Vladimir Vasiliev NEMO 3/ SuperNEMO status Scintillator + PMT Tracking (wire chamber) Source foil (40 mg/cm 2 ) Shield radon, neutron, g 32
R&D: isotope enrichment/ purification
• 4 kg of 82 Se funded by ILIAS have been delivered from Russia.
• • purification at ILN (US) underway enrichment of Nd possible in France (MENPHIS, currently mothballed) Choice of nucleus depends on: • enrichment possibilities • • high Q bb value larger phase space lower non bb small bb 2 n background contribution Two main options: G 0 n (150Nd) / G 0 n (82Se) = 8
Q
bb
(MeV) Isotopic Abundance
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 33
2007 2008
SuperNEMO schedule summary
2009 2010 2011 2012 NEMO3 Running TDR 2013 R&D SuperNEMO BiPo1 Canfranc BiPo construction BiPo installation BiPo running @ Canfranc SuperNEMO 1 st module construction Preparation of the site construction of 20 modules 6 SuperNEMO modules running @ Canfranc Final SuperNEMO modules installation
34 1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status
Conclusion
NEMO ’ s Tracking+Calorimetry approach is unique: high background rejection - choice of isotopes - reconstruction of kinematics NEMO 3 is taking data: bb2n factory, important for understanding of backgrounds and NME -limits on bb0n using different isotopes: -T 1/2 ( 0n > 5.8 x 10 23 days); ' 111 < 1.5 x 10 y @ 90% CL for -4 100 Mo
Backup slides
1-5 July 2007, ILIAS meeting, Blaubeuren Vladimir Vasiliev NEMO 3/ SuperNEMO status 36