NEMO-3 Experiment Neutrino Ettore Majorana Observatory FIRST RESULTS Xavier Sarazin 1 for the NEMO-3 Collaboration CENBG, IN2P3-CNRS et Université de Bordeaux, France Charles University, Praha, Czech Republic CTU, Praha, Czech Republic INEEL, Idaho Falls, USA IReS, IN2P3-CNRS et Université de Strasbourg, France ITEP, Moscou, Russia JINR, Dubna, Russia Jyvaskyla University, Finland 1 LAL, IN2P3-CNRS et Université Paris-Sud, France LSCE, CNRS Gif sur Yvette, France LPC, IN2P3-CNRS et Université de Caen, France Mount Holyoke College, USA RRC Kurchatov Institute, Moscow, Russia Saga University, Saga, Japon UCL, London, Great-Britain Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

Plan of the talk: NEMO-3 Detector Measurement of  decay for several nuclei Search for  decay with 100 Mo and 82 Se

3 m 4 m B (25 G) 20 sectors Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004 Source : 10 kg of  isotopes cylindrical, S = 20 m 2, e ~ 60 mg/cm 2 Tracking detector : drift wire chamber operating in Geiger mode (6180 cells) Gas: He + 4% ethyl alcohol + 1% Ar + 0.1% H 2 O Calorimeter : 1940 plastic scintillators coupled to low radioactivity PMTs Magnetic field: 25 Gauss Gamma shield: Pure Iron (e = 18 cm) Neutron shield: 30 cm water (ext. wall) 40 cm wood (top and bottom) (since march 2004: water  boron) Able to identify e , e ,  and  The NEMO3 detector Fréjus Underground Laboratory : 4800 m.w.e.

 isotope foils scintillators PMTs Calibration tube Cathodic rings Wire chamber Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

AUGUST 2001 Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

coil Iron shield Water tank wood NEMO-3 Opening Day, July 2002 Start taking data 14 February 2003 Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

100 Mo kg Q  = 3034 keV  decay isotopes in NEMO-3 detector 82 Se kg Q  = 2995 keV 116 Cd 405 g Q  = 2805 keV 96 Zr 9.4 g Q  = 3350 keV 150 Nd 37.0 g Q  = 3367 keV Cu 621 g 48 Ca 7.0 g Q  = 4272 keV nat Te 491 g 130 Te 454 g Q  = 2529 keV  measurement External bkg measurement  search Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004 (All the enriched isotopes produced in Russia)

Drift distance 100 Mo foil Transverse view Longitudinal view Run Number: 2040 Event Number: 9732 Date: Geiger plasma longitudinal propagation Scintillator + PMT Deposited energy: E 1 +E 2 = 2088 keV Internal hypothesis: (  t) mes –(  t) theo = 0.22 ns Common vertex: (  vertex)  = 2.1 mm Vertex emission (  vertex) // = 5.7 mm Vertex emission Transverse view Longitudinal view Run Number: 2040 Event Number: 9732 Date: Criteria to select  events: 2 tracks with charge < 0 2 PMT, each > 200 keV PMT-Track association Common vertex Internal hypothesis (external event rejection) No other isolated PMT (  rejection) No delayed track ( 214 Bi rejection)  events selection in NEMO-3 Typical  2 event observed from 100 Mo Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004 Trigger: 1 PMT > 150 keV 3 Geiger hits (2 neighbour layers + 1) Trigger rate = 7 Hz  events: 1 event every 1.5 minutes

Tracking Detector:  99.5 % Geiger cells ON  Vertex resolution: 2 e  channels (482 and 976 keV) using 207 Bi sources at 3 well known positions in each sector   (  Vertex) = 0.6 cm  // (  Vertex) = 1.3 cm (Z=0)  e  /e  separation with a magnetic field of 25 G ~ 3% confusion at 1 MeV -- --  Vertex  Vertex = distance between the two vertex Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004 Time Of Flight:  Time Resolution (  channel)  250 ps at 1 MeV ToF (external crossing e  ) > 3 ns external crossing e  totaly rejected External Background  events from the foil (  t mes –  t calc ) external hypo. (ns) (  t mes –  t calc ) internal hypo. (ns) Calorimeter:  97% of the PMTs+scintillators are ON  Energy Resolution: calibration runs (every ~ 40 days) with 207 Bi sources 17%14% FWHM (1 MeV) Int. Wall 3" PMTs Ext. Wall 5" PMTs 207 Bi 2 conversion e  482 keV and 976 keV 482 keV 976 keV FWHM = 135 keV (13.8%)  Daily Laser Survey to control gain stability of each PM  gamma: efficiency ~ keV, E thr = 30 keV Expected Performance of the detector has been reached Performance of the detector

Measurement of  decay in NEMO-3 Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

(Data 14 Feb – 22 Mar. 2004) T 1/2 = 7.72  0.02 (stat)  0.54 (syst)  y 100 Mo 2  2 preliminary results 4.57 kg.y Cos(  ) Angular Distribution Background subtracted 2  2 Monte Carlo Data events 6914 g days S/B = 45.8 NEMO Mo E 1 + E 2 (keV) Sum Energy Spectrum events 6914 g days S/B = 45.8 NEMO Mo Data Background subtracted 2  2 Monte Carlo Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

Simkovic, J. Phys. G, 27, 2233, 2001 Single electron spectrum different between SSD and HSD 100 Mo 2  2 Single Energy Distribution 2  2 HSD Monte Carlo HSD higher levels Background subtracted Data 2  2 SSD Monte Carlo Background subtracted Data SSD Single State HSD: T 1/2 = 8.61  0.02 (stat)  0.60 (syst)  y SSD: T 1/2 = 7.72  0.02 (stat)  0.54 (syst)  y 100 Mo 2  2 single energy distribution in favour of Single State Dominant (SSD) decay 4.57 kg.y E 1 + E 2 > 2 MeV 4.57 kg.y E 1 + E 2 > 2 MeV HSD, higher levels contribute to the decay SSD, 1  level dominates in the decay (Abad et al., 1984, Ann. Fis. A 80, 9) 100 Mo 00 100 Tc 11   /ndf = 139. / 36   /ndf = 40.7 / 36 NEMO-3 E single (keV) Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

Background subtracted 82 Se T 1/2 = 10.3  0.2 (stat)  1.0 (syst)  y 116 Cd if SSD T 1/2 = 2.8  0.1 (stat)  0.3 (syst)  y if HSD T 1/2 = 3.05  0.1 (stat)  0.3 (syst)  y 150 Nd T 1/2 = 9.7  0.7 (stat)  1.0 (syst)  y 96 Zr T 1/2 = 2.0  0.3 (stat)  0.2 (syst)  y 82 Se 116 Cd 150 Nd 2  2 preliminary results for other nuclei 96 Zr Data  simulation Data  simulation Data  simulation Data  simulation NEMO g days 2385 events S/B = 3.3 NEMO g days 72 events S/B = g days 449 events S/B = g days 1371 events S/B = 7.5 E 1 +E 2 (keV) E 1 +E 2 (MeV) Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

Search for  decay in NEMO-3 Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

 External Background 208 Tl (PMTs) Measured with (e ,  ) external events ~ 10  3  -like events year  1 kg  1 with 2.8<E 1  E 2 <3.2 MeV  Analysis: Background Measurement <  Mo metal. 400   Se <  Mo comp. A (  Bq/kg) HPGe meas. A (  Bq/kg) from (e , N  ) sources In agreement with HPGe measurements  208 Tl impurities inside the foils Measured with (e ,2 , (e ,3  events coming from the foil ~ 0.1  -like events year  1 kg  1 with 2.8<E 1  E 2 <3.2 MeV  100 Mo  decay T 1/2 = y (SSD) ~ 0.3  -like events year  1 kg  1 with 2.8<E 1 +E 2 <3.2 MeV  External Neutrons and High Energy gamma Measured with (e ,e  ) int events with E 1  E 2  4 MeV  0.02  -like events year  1 kg  1 with 2.8<E 1  E 2 <3.2 MeV ~ Only 2 (e ,e  ) int events with E 1  E 2  4 MeV observed after 260 days of data (without boron) 4253 keV (26 Mar. 2003) 6361 keV (8 Nov. 2003) In agreement with expected background Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004 NEMO-3 can measure each component of its background !

Radon in the NEMO-3 gas of the wire chamber  Analysis: Background Measurement Due to a tiny diffusion of the radon of the laboratory inside the detector A(Radon) in the lab ~15 Bq/m Rn (3.8 days) 218 Po 214 Pb 214 Bi 214 Po 210 Pb    s ~ 1  -like events/year/kg with 2.8 < E 1 +E 2 < 3.2 MeV Radon is the dominant background today for  search in NEMO-3 !!! Two independant measurements of radon in NEMO-3 gas Good agreement between the two measurements  Radon detector at the input/output of the NEMO-3 gas ~ 20 counts/day for 20 mBq/ m 3  (1e  + 1  ) channel in the NEMO-3 data: Delayed tracks (<700  s) to tag delayed  from 214 Po 214 Bi  214 Po (164  s)  210 Pb ~ 200 counts/hour for 20 mBq/m 3 A(Radon) in NEMO-3  mBq/m 3 Decay in gas  delayed  214 Bi  214 Po (164  s)  210 Pb   Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

 Analysis with 100 Mo V-A: T 1/2 (  ) > y V+A: T 1/2 > y with  E 1 - E 2  > 800 keV Majoron: T 1/2 > y with E single > 700 keV Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June Mo     7.0 TOTAL Monte-Carlo 2.6<E 1 +E 2 <3.2 50DATA 23.5  6.7 Radon M-C 32.3  Mo 2  2  M-C 100 Mo 6914 g 265 days Data  Monte-Carlo Radon Monte-Carlo E 1 +E 2 (MeV)  arbitrary unit PRELIMINARY 2.6<E 1 +E 2 <3.2 Cu + nat Te Te 265 days Radon Monte-Carlo Data E 1 +E 2 (MeV) Cu + nat Te Te  3.4 ____ 2.6  ____ 2.6<E 1 +E 2 <3.2

100 Mo  likelihood analysis 3 variables used for the likelihood Ec 1 + Ec 2 sum of the kinetic energies of the 2 e  Ec min energy of the e  of minimal energy Cos  angle between the two tracks Ec = Energy at the exit of the 100 Mo foil = Energy deposited in scintillator (E) + energy losses in the tracking detector x   is the free parameter N  N tot L calculated with  events Ec 1 +Ec 2 >2 MeV -- -- Cos  Ec 1 Ec 2 E1E1 E2E2 ! Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

100 Mo  likelihood analysis Ec 1 +Ec 2 (keV) Data  Monte-Carlo Radon Monte-Carlo 100 Mo 6914 g days 4.10 kg.y PRELIMINARY Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004 Data  Monte-Carlo Radon Monte-Carlo  T 1/2 = Mo 6914 g days 4.10 kg.y Ec 1 +Ec 2 (keV) Previous limit V-A: T 1/2 (  ) > y (Elegant V, Ejiri et al., 2001) V-A: T 1/2 (  ) > y (90% C.L.) V+A: T 1/2 > y (90% C.L.) -Log(Likelihood) x   N  N tot

Previous limit V-A: T 1/2 (  ) > y (NEMO-2) Arnold et al. Nucl. Phys. A636 (1998) 82 Se  likelihood analysis PRELIMINARY Data  Monte-Carlo Radon Monte-Carlo 82 Se 932 g days 0.55 kg.y Data  Monte-Carlo Radon Monte-Carlo 82 Se 932 g days 0.55 kg.y Ec 1 +Ec 2 (keV) V-A: T 1/2 (  ) > y (90% C.L.) V+A: T 1/2 > y (90% C.L.) Majoron: T 1/2 > y (90% C.L.) Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

Limit on the effective mass of the Majorana neutrino, on Majoron and on V+A Limits on T 1/2 90% C.L. Limit on Majoron 100 Mo: T 1/2 > y  < (5.3 – 8.5) 10  5 Simkovic (1999), Stoica (1999) 82 Se: T 1/2 > y  < (0.7 – 1.6) 10  4 Simkovic (1999), Stoica (2001) Limit on V+A 100 Mo: T 1/2 > y  < (1.5 – 2.0) 10  6 Tomoda (1991), Suhonen (1994) 82 Se: T 1/2 > y <  6 Tomoda (1991) Simkovic et al., Phys. Rev. C60 (1999) Stoica, Klapdor, Nucl. Phys. A694 (2001) Simkovic et al., Phys. Rev. C60 (1999) Stoica, Klapdor, Nucl. Phys. A694 (2001) Caurier et al., Phys. Rev. Lett (1996) Limit on the Majorana neutrino effective mass 100 Mo: T 1/2 (  ) > y  m  < 0.7 – 1.2 eV 82 Se: T 1/2 (  ) > y  m  < 1.3 – 3.6 eV Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

May 2004 : Tent surrounding the detector Today: A( 222 Rn) in the LSM ~ 15 Bq/m 3 August 2004 : Radon-free SuperKamiokande-like Air Factory Expected activity: A( 222 Rn) ~ 0.2 Bq/m m 3 /h 500 kg -40 o C Free-Radon Purification System in construction Today Radon is the dominant background for NEMO-3 May 2004 Expected Purification Factor ~ 75 Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004 Factor ~ 10 too high

NEMO-3 Expected sensitivity (after Radon purification) Background :  External Background is negligible  Internal Background: 208 Tl : 100  Bq/kg for 100 Mo 300  Bq/kg for 82 Se 214 Bi : < 300  Bq/kg ~ 0.1 count kg  1 y  1 with 2.8<E 1 +E 2 <3.2 MeV   : T 1/2 = y (SSD) ~ 0.3 count kg  1 y  1 with 2.8<E 1 +E 2 <3.2 MeV 5 years of data 6914 g of 100 Mo T 1/2 (  )  y (90% C.L.)  m  < 0.2 – 0.35 eV 932 g of 82 Se T 1/2 (  )  y (90% C.L.)  m  < 0.65 – 1.8 eV (conservative limit) Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

CONCLUSIONS  NEMO-3 Detector running since 14 Feb Expected performance of the detector has been reached !   preliminary results for 100 Mo, 82 Se, 96 Zr, 116 Cd and 150 Nd already more than  events collected 100 Mo: in favour of Single State Dominance (SSD) 100 Mo  decay to excited state has been measured with ~ 4   Preliminary T 1/2 (  ) limit (216.4 days of data): 100 Mo (4.10 kg.y) T 1/2 (  ) > y   m  < 0.7 – 1.2 eV 82 Se (0.55 kg.y) T 1/2 (  ) > y   m  < 1.3 – 3.6 eV  Level of backgounds as excepted except Radon ~ 10 times too high Free radon purification system in operation in August 2004 Supression factor ~ 75  Expected sensitivity in 5 years after radon purification 100 Mo: T 1/2 (  ) > y  m  < 0.2 – 0.35 eV 82 Se: T 1/2 (  ) > y  m  < 0.65 – 1.8 eV Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004