1. First results from KamLAND
M.Motoki　（Tohoku University)
For the KamLAND Collaboration

2. Neutrino Oscillation SuperK day night, SuperK energy spectrum
 LMA+LOW
LMA
SNO NC; ne+nm+nt
SMA
Flavor transition
day/night
LMA
LOW
KamLAND;
Artificial neutrino sources
Low energy
Long baseline
VAC

3. KamLAND Kamioka Liquid scintillator Anti Neutrino Detector
Reactor Anti Neutrino Source.
Energy distortion, LMA
7Be neutrinos.
Geo neutrinos.

4. The KamLAND Collaboration
K.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 University
J.Busenitz, Z.Djurcic, K.McKinny, D.-M.Mei, A.Piepke, E.Yakushev,
University of Alabama
B.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 Berkeley
G.A.Horton-Smith, R.D.McKeown, J.Ritter, B.Tipton, P.Vogel
California Institute of Technology
C.E.Lane, T.Miletic
Drexel University
P.W.Gorham, G.Guillian, J.G.Learned, J.Maricic, S.Matsuno, S.Pakvasa
University of Hawaii
S.Dazeley, S.Hatakeyama, M.Murakami, R.C.Svoboda
Louisiana State University
B.D.Dieterle, M.DiMauro
University of New Mexico
J.Detwieler, G.Gratta, K.Ishii, N.Tolich, Y.Uchida
Stanford University
M.Batygov, W.Bugg, H.Cohn, Y.Efremenko, Y.Kamyshkov, A.Kozlov, Y.Nakamura
University of Tennessee
L.De Braeckeleer, C.R.Gould, H.J.Karwowski, D.M.Markoff, J.A.Messimore, K.Nakamura, R.M.Rohm, W.Tornow, A.R.Young
TUNL
Y.-F.Wang
IHEP,Beijing

5. Suitable to test LMA solution
a few /day in KamLAND
54 Japanese Reactors
Average distance 180km
(79 % in km)
< Eν> ～ 4MeV
⊿m2 ～E/L ～10-5 eV2
Suitable to test LMA solution

6. Reactor 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
Uncertainty : 2.5% for anti νe

8. Reactor Neutrino detection in Liquid Scintillator

9. Vertex reconstruction
Using PMT timing information
Source Calibration Data: Z-axis
Typically 25cm resolution
Position reconstruction: 5cm

10. Vertex Fitter Performance: Fiducial Volume

11. Energy resolution 68Ge ( + ) : 1.012 MeV 65Zn () : 1.116 MeV
Along to Z-axis: radioactive source
68Ge ( + ) : MeV
65Zn () : MeV
60Co ( + ) : MeV
AmBe (,n) : , 4.40, 7.6 MeV
time dependence: 0.6%
4πcalibration: captured netron events
n+pd+g : MeV
n+12C13C+g : 4.9MeV
position dependence: 1.1%
DE/E ~ 7.5% /√E [MeV]
DEsyst=1.9% at 2.6MeV
 2.1% for anti ne

14. Radio active Background in LS

15. 214Bi – 214Po – 210Pb Signal 238U = (3.5±0.5)x10-18 g/g b+g t = a
prompt
delayed
238U = (3.5±0.5)x10-18 g/g
b+g
DT = |tprompt – t delayed|
t =
(214Po:a)
= 237 ms a

16. Delayed coincidence

20. Vertex position after delayed coincidence

21. Prompt
Delayed

23. KamLAND result Mar. 4 – Oct. 6, 2002 162 ton•yr (145.1 days)
Observed events (E>2.6MeV)
Background 1 ± 1 events
Expected ± 5.6 events
Geo Neutrino: 0 – 110 TW (95 % C.L.)

24. Spectral Distortion? Need more reactor neutrino and calibration data
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

25. KamLAND impacts
95%CL
LMA 2
LMA 1
KamLAND
All combined

26. KamLAND Prospects Neutrino Oscillation? Precision measurements 7Be
Energy Spectrum distortion?
Current reactor power in Japan ~50%.
A new reactor is coming.
LMA 1 or LMA2
7Be
Purification system improvement

29. LMA I, LMA II
Before and After
New Reactor “Shika”

30. KamLAND Solar

31. Summary Last year Future
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.

32. Appendix

33. Solar Neutrino at KamLAND
First observation of real time 7Be neutrinos