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motoki@NDM03
M.Motoki ( Tohoku University)For the KamLAND Collaboration
First results from KamLAND
motoki@NDM03
SNO NC; e++
Flavor transitionday/night
LMA
NeutrinoNeutrino OscillationOscillation
KamLAND; Artificial neutrino sourcesLow energy Long baseline
LMA
SMA
LOW
VAC
SuperK day night, SuperK energy spectrum LMA+LOW
motoki@NDM03
KamLANDKamLANDKamKamiokaioka LLiquid scintillator iquid scintillator AAnti nti NNeutrino eutrino DDetectoretector
Reactor Anti Neutrino Source.Reactor Anti Neutrino Source. Energy distortion, LMAEnergy distortion, LMA 77Be neutrinos.Be neutrinos. Geo neutrinos.Geo neutrinos.
motoki@NDM03
The KamLAND CollaborationK.Eguchi, S.Enomoto, K.Furuno, J.Goldman, H.Hanada, H.Ikeda, K.Ikeda, K.Inoue, K.Ishihara, W.Itoh, T.Iwamoto, T.Kwaguchi, T.Kawashima, H.Kinoshita, Y.Kishimoto, M.Koga, Y.Koseki, T.Maeda, T.Mitsui, M.Motoki, K.Nakajima, M.Nakajima, T.Nakajima, H.Ogawa, K.Owada,
T.Sakabe, I.Shimizu, J.Shirai, F.Suekane, A.Suzuki, K.Tada, O.Tajima, T.Takayama, K.Tamae, H.Watanabe
Tohoku UniversityJ.Busenitz, Z.Djurcic, K.McKinny, D.-M.Mei, A.Piepke, E.Yakushev,
University of AlabamaB.E.Berger, Y.D.Chan, M.P.Decowski, D.A.Dwyer, S.J.Freedman, Y.Fu, B.K.Fujikawa, K.M.Heeger, K.T.Lesko, K.-B.Luk, H.Murayama, D.R.
Nygren, C.E.Okada, A.W.P.Poon, H.M.Steiner, L.A.Winslow
LBNL/UC BerkeleyG.A.Horton-Smith, R.D.McKeown, J.Ritter, B.Tipton, P.Vogel
California Institute of TechnologyC.E.Lane, T.Miletic
Drexel UniversityP.W.Gorham, G.Guillian, J.G.Learned, J.Maricic, S.Matsuno, S.Pakvasa
University of HawaiiS.Dazeley, S.Hatakeyama, M.Murakami, R.C.Svoboda
Louisiana State UniversityB.D.Dieterle, M.DiMauro
University of New MexicoJ.Detwieler, G.Gratta, K.Ishii, N.Tolich, Y.Uchida
Stanford UniversityM.Batygov, W.Bugg, H.Cohn, Y.Efremenko, Y.Kamyshkov, A.Kozlov, Y.Nakamura
University of TennesseeL.De Braeckeleer, C.R.Gould, H.J.Karwowski, D.M.Markoff, J.A.Messimore, K.Nakamura, R.M.Rohm, W.Tornow, A.R.Young
TUNLY.-F.Wang
IHEP,Beijing
motoki@NDM03
a few /day in KamLAND
• 54 Japanese Reactors
• Average distance 180km
• (79 % in 138-214km)
• < Eν> ~ 4MeV
• ⊿m2 ~ E/L ~ 10-5 eV2
• Suitable to test LMA solution
motoki@NDM03
Reactor neutrino flux at KamLANDReactor neutrino flux at KamLAND
• Thermal power, Burn-up, : available for All 54 Japanese Reactors• Reactor type, Volume ratio of new fuel, Enrichment of new fuel, initial mean burn up• Simple model of reactor core.
– fission rate– energy spectrum @KamLANDUncertainty : 2.5% for anti νe
motoki@NDM03
motoki@NDM03
Reactor Neutrino detection in Liquid Scintillator
motoki@NDM03
Vertex reconstructionVertex reconstruction
Typically 25cm resolutionPosition reconstruction: 5cm
Using PMT timing information
Source Calibration Data: Z-axis
motoki@NDM03
Vertex Fitter Performance: Fiducial Volume
motoki@NDM03
Energy Energy resolutionresolution
Along to Z-axis: radioactive source68Ge ( + ) : 1.012 MeV 65Zn () : 1.116 MeV 60Co ( + ) : 2.506 MeV AmBe (,n) : 2.20, 4.40, 7.6 MeV time dependence: 0.6%
4πcalibration: captured netron events n+pd+MeVn+12C13C+: 4.9MeV position dependence: 1.1%E/E ~ 7.5% /√E [MeV]Esyst=1.9% at 2.6MeV
2.1% for anti e
motoki@NDM03
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Radio active Background Radio active Background in LSin LS
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T = |tprompt – t delayed|
214Po:s
214214Bi – Bi – 214214Po – Po – 210210Pb SignalPb Signaldelayedprompt
238U = (3.5±0.5)x10-18 g/g
motoki@NDM03
Delayed coincidence
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Vertex position after Vertex position after delayed coincidencedelayed coincidence
motoki@NDM03
Prompt
Delayed
motoki@NDM03
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KamLAND KamLAND resultresult
)(041.0
)(085.0611.0N
NN
expected
bgobs
sys
stat
Mar. 4 – Oct. 6, 2002162 ton•yr (145.1 days)
Observed 54 events (E>2.6MeV)
Background 1 ± 1 events
Expected 86.8 ± 5.6 events
Geo Neutrino: 0 – 110 TW (95 % C.L.)
motoki@NDM03
Spectral Distortion?Spectral Distortion?
2- oscillation: best-fit No oscillation, flux suppression
Data and best oscillation fit
consistent at 93% C.L. Data and scaled no-oscillation shape consistent at 53% C.L
Need more reactor neutrino and calibration data
motoki@NDM03
KamLAND impactsKamLAND impacts
95%CL
Best fit LMA KamLAND
sin22 0.833 1.0m2[eV2] 5.5 x 10-5 6.9 x 10-5
KamLAND All combined
LMA 2
LMA 1
motoki@NDM03
KamLAND ProspectsKamLAND Prospects
• Neutrino Oscillation? Precision measurements– Energy Spectrum distortion?
– Current reactor power in Japan ~50%.
– A new reactor is coming.
– LMA 1 or LMA2
• 7Be – Purification system improvement
motoki@NDM03
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LMA I, LMA IIBefore and AfterNew Reactor “Shika”
motoki@NDM03
KamLANKamLAND D
SolarSolar )%99%(4.4 CL
motoki@NDM03
SummarySummary Last year
– KamLAND saw a clear deficit in reactor neutrinos.
• Future– KamLAND purification system will be improved for
7Be Solar Neutrino detection.– Stable data taking during reactor shutdown.– LMA1,LMA2 will be decided.
motoki@NDM03
Appendix
motoki@NDM03
Solar Neutrino at Solar Neutrino at KamLANDKamLAND
First observation of real time 7Be neutrinos
Background Current Goal Method238U 3.5 ×10-18g/g OK
232Th 5.2 ×10-17g/g OK222Rn 3.3×10-8Bq/m-3 OK
40K <2.7 ×10-16g/g <10-18g/g Water Extraction210Pb ~10-20g/g 5 ×10-25g/g Water Extraction85Kr 0.7Bq/m-3 10-6Bq/m-3 N2 purge
222Rn leak N2 purge/ air tight valves
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