Transcript NEMO/SuperNEMO. Status and prospects.

NEMO-III
Status and prospects.
12 December 2005
HEP group Christmas meeting
Vladimir Vasiliev
Plan
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2b0n decay and neutrino mass
NEMO-III experiment
what we did in 2005
UCL contribution and future prospects
2b decay and neutrino
mass
DL=0
2n
1/ 2
-1
2n
T (0  0 )   G ( E0 , Z ) M
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2n 2
DL=2 !
0n
1/ 2
-1
0n
T (0  0 )   G ( E0 , Z ) M

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0n 2
 mn 2
Can happen if
• neutrino has a mass (proved)
• neutrino is a Majorana particle (not proved,
but highly suspected)
Why to like Majorana?
MR
mL
See-Saw: why small mn
mL 
2
D
m
MR
Leptogenesis:
why something, not nothing.
Isn’t it just too boring for nature, if all
particles are Dirac ones?
Experimental signature
a) 2 electrons
b) fixed energy
Until 2009 only 2 big
experiments will be running
• Couricino, b) only
• NEMO-III, a) and b)
Qbb
NEMO-III experiment
2004
2005
bb decay isotopes in NEMO-3 detector
bb2n measurement
116Cd
405 g
Qbb = 2805 keV
96Zr
9.4 g
Qbb = 3350 keV
150Nd
37.0 g
Qbb = 3367 keV
48Ca
7.0 g
Qbb = 4272 keV
130Te
454 g
Qbb = 2529 keV
100Mo
6.914 kg
Qbb = 3034 keV
82Se
0.932 kg
Qbb = 2995 keV
bb0n search
natTe
491 g
Cu
621 g
External bkg
measurement
(All the enriched isotopes produced in Russia)
Phase-I
(02.2003-10.2004)
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Detector background study
Precise measurement of 2b2n
2b2n to excited states
Anti-Radon facility
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Installed October 2004
0.5 t charcoal @ -45C
A(222Rn) from 20
Bq/m3 to 0.2 Bq/m3
Should get read of
ultimate natural
radioactivity BG: 222Rn
Proof of principle that
zero BG experiment is
possible
Latest results, Mo
PRL 95, 182302 (2005)
T1/2 = 7.11 ± 0.02 (stat) ± 0.54 (syst)  1018 y, SSD mechanism!
T0n > 4.6  1023 y , mn < 0.7-2.8 eV
Latest results, Se
PRL 95, 182302 (2005)
T1/2 = 9.6 ± 0.3 (stat) ± 1.0 (syst)  1019 y
T0n > 1.0  1023 y , mn < 1.7-4.9 eV
Latest results, excited states
to be published soon
T1/2 (0-0)= 5.6 ± 1.5 (stat) ± 0.6 (syst)  1020 y
T1/2 (0-2)> 1021 y
T0n (0-2)> 1.2  1023 y , l < 1.3  10-4
NEMO work at UCL
•Hardware
• PMT ageing in the helium (R. Saakyan)
• LED light injection system as alternative to laser
(J. Thomas, S. Williamson, R.Saakyan)
•Data analysis
• ROOT based framework for analysis (V. Vasiliev)
• Mo decay to excited states (J. Thomas, S. King, V.
Vasiliev)
• 2b2n decay of Te and Ca (R. Saakyan, S. King)
Future prospects
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Analyze low background phase II data.
Develop full 3D likelihood for 0n search
Try to improve tracking software
At present conditions we can reach
sensitivity at 0.3 eV in few years.
Challenging goal is go down to ~0.2 eV*
* Klapdor-Kleingrothaus interval is [0.1-0.9] eV, best fit 0.44 eV (2004)
WE ARE IN THE MIDDLE OF THE ROAD
EXIT
THAT COULD LEAD BEYOND SM