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