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NEMO-IIINEMO-IIIStatus and Status and prospects.prospects.
12 December 200512 December 2005
HEP group Christmas meetingHEP group Christmas meeting
Vladimir Vasiliev Vladimir Vasiliev
PlanPlan
decay and neutrino mass decay and neutrino mass experimentexperiment what we did in 2005what we did in 2005 UCL contribution and future UCL contribution and future
prospectsprospects
decay and neutrino decay and neutrino massmass
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 !
Can happen if • neutrino has a mass (proved)• neutrino is a Majorana particle (not proved, but highly suspected)
Why to like Majorana?Why to like Majorana?
Isn’t it just too boring for nature, if all Isn’t it just too boring for nature, if all particles are Dirac ones?particles are Dirac ones?
MR
mL
See-Saw: why small m Leptogenesis: why something, not nothing.R
DL M
mm
2
Experimental Experimental signaturesignature
a) 2 electronsb) fixed energy
Q
Until 2009 only 2 big experiments will be running
• Couricino, b) only• NEMO-III, a) and b)
NEMO-III experimentNEMO-III experiment
2004
2005
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)
Phase-I Phase-I (02.2003-10.2004) (02.2003-10.2004)
Detector background study Detector background study Precise measurement of Precise measurement of to excited statesto excited states
Anti-Radon facilityAnti-Radon facility
Installed October 2004Installed October 2004 0.5 t charcoal @ -450.5 t charcoal @ -45CC A(A(222222Rn) from 20 Bq/mRn) from 20 Bq/m3 3
to 0.2 Bq/mto 0.2 Bq/m33
Should get read of Should get read of ultimate natural ultimate natural radioactivity BG: radioactivity BG: 222222RnRn
Proof of principle that Proof of principle that zero BG experiment is zero BG experiment is possiblepossible
Latest results, Mo Latest results, Mo PRL 95, 182302 (2005)PRL 95, 182302 (2005)
T1/2 = 7.11 0.02 (stat) 0.54 (syst) 1018 y, SSD mechanism!T > 4.6 1023 y , m< 0.7-2.8 eV
Latest results, Se Latest results, Se PRL 95, 182302 (2005)PRL 95, 182302 (2005)
T1/2 = 9.6 0.3 (stat) 1.0 (syst) 1019 yT > 1.0 1023 y , m< 1.7-4.9 eV
Latest results, excited Latest results, excited states states
to be published soonto be published soon
T1/2 (0-0)= 5.6 1.5 (stat) 0.6 (syst) 1020 yT1/2 (0-2)> 1021 yT (0-2)> 1.2 1023 y , < 1.3 10-4
NEMO work at UCLNEMO 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) • decay of Te and Ca (R. Saakyan, S. King)
Future prospectsFuture prospects
Analyze low background phase II data.Analyze low background phase II data. Develop full 3D likelihood for Develop full 3D likelihood for searchsearch Try to improve tracking softwareTry 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