Double beta decays of 100Mo and Molybdenum Observatory Of Neutrinos(MOON)

Introduction Neutrino studied by 100Mo ELEGANT V and Oto Cosmo Observatory Molybdenum Observatory Of Neutrinos (MOON) Concluding Remarks

Collaborators(Japan-USA)

K.Fushimi1,H.Ejiri2,J.Engel4,K.Hayashi5,R.Hazama3

T.Kishimoto6,P.Krastev7,N.Kudomi5,K.Kume5,H.Kuramoto5,

K.Matsuoka6,M.Nomachi6,H.Ohsumi8,R.G.H.Robertson3, K.Takahisa5, and S.Yoshida5 1. Dept. of Physics, The Univ. of Tokushima2. International Institute for Advanced Studies3. Nuclear Physics Lab.and Dept. of Physics, Univ. of Washington4. Dept. of Physics and Astronomy, Univ. of North Carolina5. RCNP, Osaka Univ.6. Dept. of Physics, Osaka Univ.7. Dept. of Physics, Univ. of Wisconsin8. Dept. of Physics, Saga Univ.

Introduction

Double Beta Decay and Neutrino Properties Neutrino Property

Mass <m> RHC <RHC>

SN and Solar Neutrino Majoron

Neutrino studied by 100Mo

Double Beta Decay 100Mo -> 100Ru Q=3.034MeV

Solar Neutrino SN Neutrino

100Mo -> 100Tc QEC=0.168MeV

ELEGANT V and Oto Cosmo Observatory

100km from Osaka 150km from Tokushima Cosmic ray

4X10-7/cm2/s (1/100000) Neutron

4X10-5/cm2/s (1/100) 222Rn

10Bq/m3 (Same as outside)

ELEGANT V ELEGANT V (ELEctron Gamma-ray Neutri

no Telescope) 100Mo Source film Drift chamber Plastic Scintillator NaI(Tl) Scintillator

ELEGANT VNIM A302 (1991) 304

BFGTBνββB/ Gχ||M|g|T 2221021 )1(][

Single Majoron Emitting decay

0B decay of 100Mo

Measurement by EL V at Oto

Experimental data 0.14 kg yr 2

1.15X1019yr BG U,Th (MC simulation)

Limits on <gB>

Nucleus

T0B1/2

X1021(yr)

|<gB>|X10-4

Ref.

100Mo 2.1 1.4 Present Worksubmitted PLB

100Mo 0.6 2.2 Nucl.Phys.A678(00)341

76Ge 64 0.83 hep-ph/0103062

136Xe 7.2 1.7 Phys.Let.B434(98)407

150Nd 0.28 1.1 Phys. Rev. C56(97)2451

Limits on other modesKamioka(7333hr) and Oto(7562hr)Phys. Rev. C63(01) 065501

Mode Yield(COUNTS)

2nbb+BG(COUNTS)

efficiency

T1/2

(1022yr)

<m> 3 4.1 0.19 >5.5(10)

1 1.8 0.17

<> 3 4.1 0.11 >3.4(6.4)

1 1.8 0.11

<>’ 0 0.6 0.075 >4.2(8.5)

0 0.4 0.063

<> 3 4.1 0.18 >4.9(9.3)

1 1.8 0.14

MOON Objectives . Spectroscopic real-time studies of tw

o rays from 100Mo. Double beta () decays with sensiti

vity of m~0.03 eV. Individual low energy solar and sup

ernova by inverse followed by successive

Phys. Rev. Lett. 85 (00) 291

Solar- capture rates in units of SNU

Nucleus -Q(MeV) pp 7Be 13N pep 15O 8B Total

2H 1.442 0 0 0 0 ---- 6 6

37Cl 0.814 0 1.1 0.1 0.2 0.3 6.1 7.9

40Ar >1.505 0 0 0 0 0 7.2 7.2

71Ga 0.236 70.8 35 3.7 2.9 5.8 12.9 132

100Mo 0.168 639 206 22 13 32 27 965

115In 0.120 468 116 13.6 8.1 18.5 14.4 639

127I 0.789 0 9.4 ---- ---- ---- 13 24.6

MOON

MOON, a super modules of nMo/100Mo& 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 100Mo 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.

MOON Plastic fiber-Mo Ensemble

Concluding remarks

100Mo as Neutrino Microlaboratory Large responses for , Solar-, SN- ELEGANT V Stringent limits on <m>, Majoron etc. MOON

Realtime spectroscopic studies of Majorona m~0.03eV Low Energy Solar Neutrino and SN neutrino