2. Double beta decays of 100 Mo and Molybdenum Observatory Of Neutrinos(MOON) Introduction Neutrino studied by 100 Mo ELEGANT V and Oto Cosmo Observatory Molybdenum Observatory Of Neutrinos (MOON) Concluding Remarks

3. Collaborators(Japan-USA) K.Fushimi 1,H.Ejiri 2,J.Engel 4,K.Hayashi 5,R.Hazama 3 T.Kishimoto 6,P.Krastev 7,N.Kudomi 5,K.Kume 5, H.Kuramoto 5, K.Matsuoka 6,M.Nomachi 6,H.Ohsumi 8, R.G.H.Robertson 3, K.Takahisa 5, and S.Yoshida 5 1. Dept. of Physics, The Univ. of Tokushima 2. International Institute for Advanced Studies 3. Nuclear Physics Lab.and Dept. of Physics, Univ. of Washington 4. Dept. of Physics and Astronomy, Univ. of North Carolina 5. RCNP, Osaka Univ. 6. Dept. of Physics, Osaka Univ. 7. Dept. of Physics, Univ. of Wisconsin 8. Dept. of Physics, Saga Univ.

4. Introduction Double Beta Decay and Neutrino Properties  Neutrino Property Mass RHC  SN and Solar Neutrino  Majoron

5. Neutrino studied by 100 Mo Double Beta Decay 100 Mo -> 100 Ru Q  =3.034MeV Solar Neutrino SN Neutrino 100 Mo -> 100 Tc Q EC =0.168MeV

6. ELEGANT V and Oto Cosmo Observatory 100km from Osaka 150km from Tokushima Cosmic ray 4X10 -7 /cm 2 /s (1/100000) Neutron 4X10 -5 /cm 2 /s (1/100) 222 Rn 10Bq/m 3 (Same as outside)

7. ELEGANT V ELEGANT V (ELEctron Gamma-ray Neutrino Telescope) 100 Mo Source film Drift chamber Plastic Scintillator NaI(Tl) Scintillator

8. ELEGANT V NIM A302 (1991) 304

10. Single Majoron Emitting  decay 0  B decay of 100 Mo

11. Measurement by EL V at Oto Experimental data 0.14 kg yr 2      1.15X10 19 yr BG U,Th (MC simulation)

12. Limits on Nucleus T 0  B 1/2 X10 21 (yr) | X10 -4 Ref. 100 Mo2.11.4 Present Work submitted PLB 100 Mo0.62.2 Nucl.Phys.A678 (00)341 76 Ge640.83 hep-ph/0103062 136 Xe7.21.7 Phys.Let. B434(98)407 150 Nd0.281.1 Phys. Rev. C56(97) 2451

13. Limits on other modes Kamioka(7333hr) and Oto(7562hr) Phys. Rev. C63(01) 065501 ModeYield (COUNTS) 2nbb+BG (COUNTS) efficiencyT 1/2 (10 22 yr) 34.10.19>5.5(10) 11.80.17 34.10.11>3.4(6.4) 11.80.11 ’ 00.60.075>4.2(8.5) 00.40.063 <><> 34.10.18>4.9(9.3) 11.80.14

14. MOON Objectives. Spectroscopic real-time studies of two  rays from 100 Mo. Double beta (  ) decays with sensitivity of m ~0.03 eV. Individual low energy solar and supernova by inverse  followed by successive  Phys. Rev. Lett. 85 (00) 291

15. Solar- capture rates in units of SNU Nucleus-Q(MeV)pp 7 Be 13 Npep 15 O 8B8BTotal 2H2H1.4420000----66 37 Cl0.81401.10.10.20.36.17.9 40 Ar>1.505000007.2 71 Ga0.23670.8353.72.95.812.9132 100 Mo0.16863920622133227965 115 In0.12046811613.68.118.514.4639 127 I0.78909.4---- 1324.6

16. 100 Mo 

17. MOON MOON, a super modules of n Mo/ 100 Mo& scintillators with modest volume and realistic purity. High position resolution and adequate time window for two  rays reduce correlated and accidental BG. MOON with ~1 ton 100 Mo is used for spectroscopic & real-time studies of Majorana with sensitivity of m ~0.03 eV by  Low E solar and supernova  by inverse  tagged by successive .

18. MOON Plastic fiber-Mo Ensemble

19. Concluding remarks 100 Mo as Neutrino Microlaboratory Large responses for , Solar-, SN- ELEGANT V Stringent limits on, Majoron etc. MOON Realtime spectroscopic studies of Majorona m ~0.03eV Low Energy Solar Neutrino and SN neutrino