1. FIRST RESULTS OF THE NEMO 3 EXPERIMENT Laurent SIMARD LAL Orsay (France) HEP-EPS 2003 conference CENBG, IN2P3-CNRS et Université de Bordeaux, France CFR, CNRS Gif sur Yvette, France FNSPE, Prague University, Czech Republic INEEL, Idaho Falls, USA IReS, IN2P3-CNRS et Université de Strasbourg, France INR RAS, Moscow, Russia ITEP, Moscow, Russia JINR, Dubna, Russia Jyvaskyla University, Finland LAL, IN2P3-CNRS et Université Paris-Sud, France LPC, IN2P3-CNRS et Université de Caen, France Mount Holyoke College, USA RRC “Kurchatov Institute”, Moscow, Russia Saga University, Japan University College London, United Kingdom NEMO collaboration

2.  L = 2 Process  Majorana Neutrino  and effective mass  Right-handed current in weak interaction  SUSY particle exchange  Majoron emission  (0 ) : 2n  2p+2e - WW WW n n p p ee ee M eR eL ( ) h h Double bêta  (0 ) decay : Physics beyond the standard model (Q  ~ MeV)

3. B 25 G 3 m located in the Laboratoire Souterrain de Modane (4800 mwe)  10 kg of  isotopes(surface: 20 m 2, thickness: 60  m for 100 Mo) 6180 drift cells operating in Geiger mode: (Helium+ethyl alcohol (4 %) + argon (1 %)) Calorimeter : 1940 plastic scintillators coupled to low radioactivity PMs  (E)/E at 3 MeV = 3.5 % Magnetic field (25 Gauss) + Iron shielding (18 cm) + neutron shielding (35 cm water +wood) Source : Tracking : Shielding : Calorimeter : The NEMO3 detector

4. June 2002 : tests runs February 2003 : beginning of data taking The NEMO3 detector AUGUST 2001

5. 7.2 kg 100 Mo 1 kg 82 Se 0.4 kg 116 Cd 0.6 kg 130 Te 1 kg nat Te 0.6 kg Cu   background  48 g 150 Nd 20 g 96 Zr 7 g 48 Ca The sources in NEMO3

6. Identification of the particles : e, ,  Calorimeter  Magnetic field Distinction between e - and e + Tracking Distinction between e and  Delayed track (  until 700  s Potentialities of the NEMO3 detector

7. Canal 1 e-:    1 MeV) =  cm;    0.5 MeV) =  cm    1 MeV) =  cm;    0.5 MeV) =  cm Reconstruction of vertex (runs with 207 Bi sources) Performances of the NEMO3 detector Energy calibration(with 207 Bi and 90 Sr sources) 207 Bi 482 keV 976 keV 207 Bi : 0.5 MeV and 1 MeV 90 Sr : 2.3 MeV      1 MeV) =  ADC channel

8. Selection of electron-electron events 1256 keV 832 keV 2 e- tracks associated with PMs hits, originated from the same vertex on the foil Time of flight : decay in the source No delayed hit near the vertex (rejection of  )

9. S/B~100 si E1+E2 > 1000 keV 100 Mo 2  2 preliminary results Feb-Mar 2003

10. Background substracted NEMO 3 2  2 Monte Carlo 100 Mo 2  2  angular distribution

11. 1850 hours 400 events S/B = 4 Background substracted Contaminated with  - emitters Cuts: E > 300 keV, Cos (  ) < 0.7 NEMO 3 2  2 Monte Carlo 82 Se 2  2  preliminary result

12. Measurement of the background processes, in other channels : 214 Bi Channel e (  with T 1/2 (  ) ~ 164  s ( 214 Bi -  214 Po -  210 Pb  ) 208 Tl Channels e  ’s with E  = 2.6 MeV neutrons, and external gammas e- crossing > 4 MeV Background at high energy 2 isotopes which have the greater Q  values : 214 Bi : Q   3.27 MeV 208 Tl : Q   MeV

13. Study of the background : 208 Tl A( 208 Tl in 100 Mo foils) < 100  Bq/kg look for e , e2 , e3  events coming from the foil

14. Study of the background : 214 Bi ~1  0 -like  event due to radon expected in a year (same order of magnitude as the sum of other backgrounds) anti-radon tent in fall 2003 air radon free factory in summer 2004 « anti-radon » tent Specification : A( 214 Bi in 100 Mo) < 300  Bq/kg main effect : 222 Rn (parent of 214 Bi) found in the gas volume for the moment no limit given on A( 214 Bi in 100 Mo) 2 measurements of 222 Rn activity by NEMO 3 itself (events e  (n  )) by radon monitor for the chamber out gas A( 222 Rn inside NEMO3) ~ 30 mBq/m 3

15. Efficiency (  in[2.8-3.2] MeV 14 % Internal Background: 208 Tl < 0.3 events/year 214 Bi < 0.3 events /year  0.8 events /year External Background: 0. events /year For 7 kg of 100 Mo(Q  = 3.038 MeV) < ~1.4 background events expected in one year after 5 years data taking T 1/2 >8. 10 24 y  m   < 0.1 - 0.4 eV For 1 kg of 82 Se (Q  = 2.995 MeV) Rejection of « hots spots » < 0.03 background events expected in one year after 5 years data taking T 1/2 > 1.5 10 24 y  m   < 0.6 - 1.2 eV Sensitivity of the NEMO3 detector (limits at the 90% CL level)

16. NEMO 3 is running Physics runs in LSM since February 14 th 2003 (~1700 h of data collected until end of May 2003) T     7.8 10 18 y (stat error ~1 %) 1/2 T    Se  9.1 10 19 y (stat error ~4 %) 1/2 Conclusion Study of detector performance with tests runs (june to december 2002) tracking and calorimeter performance in agreement with design Results for  0 in 2004

17. N S E W Fall 2003 : A( 222 Rn) ~5 Bq/m 3 Now : A( 222 Rn) in the LSM ~10 Bq/m 3 Mid 2004 : A( 222 Rn) ~0.2 Bq/m 3 Anti-radon tent for NEMO3 detector

18. HSD, higher levels contribute to the decay SSD, 1+ level dominates in the decay Abad et al., 1984, Ann. Fis. A 80, 9 Calculations for Mo: F. Simkovic et al., J. Phys. G, 27 (2001) 2233-2240 Effect in one electron spectrum NEMO High 2  2 statistics Measures each electron could see it! Mo 2  2 HSD ans SSD mechanism