Recent Results and Prospects from KamLAND

1. Recent Results and Prospects from KamLAND Nikolai Tolich

2. KamLAND Collaboration T. Araki1, K. Eguchi1, S. Enomoto1, K. Furuno1, K. Ichimura1, H. Ikeda1, K. Inoue1, K. Ishihara1, T. Iwamoto1, T. Kawashima1, Y. Kishimoto1, M. Koga1, Y. Koseki1, T. Maeda1, T. Mitsui1, M. Motoki1, K. Nakajima1, H. Ogawa1, K. Owada1, J.-S. Ricol1, I. Shimizu1, J. Shirai1, F. Suekane1, A. Suzuki1, K. Tada1, O. Tajima1, K. Tamae1, Y. Tsuda1, H. Watanabe1, J. Busenitz2, T. Classen2, Z. Djurcic2, G. Keefer2, K. McKinny2, D-M. Mei2, A. Piepke2, E. Yakushev2, B.E. Berger3, Y.D. Chan3, M.P. Decowski3, D.A. Dwyer3, S.J. Freedman3, Y. Fu3, B.K. Fujikawa3, J. Goldman3, F. Gray3, K.M. Heeger3, K.T. Lesko3, K.-B. Luk3, H. Murayama3, A.W.P. Poon3, H.M. Steiner3, L.A. Winslow3, G.A. Horton-Smith4, C. Mauger4, R.D. McKeown4, P. Vogel4, C.E. Lane5, T. Miletic5, P.W. Gorham6, G. Guillian6, J.G. Learned6, J. Maricic6, S. Matsuno6, S. Pakvasa6, S. Dazeley7, S. Hatakeyama7, A.Rojas7, R. Svoboda7, B.D. Dieterle8, J. Detwiler9, G. Gratta9, K. Ishii9, N. Tolich9, Y. Uchida9, M. Batygov10, W. Bugg10, Y. Efremenko10, Y. Kamyshkov10, A. Kozlov10, Y. Nakamura10, H.J. Karwowski11, D.M. Markoff11, J.A. Messimore11, K. Nakamura11, R.M. Rohm11, W. Tornow11, R. Wendell11, A.R. Young11, M.-J. Chen12, Y.-F. Wang12, and F. Piquemal13 1Research Center for Neutrino Science, Tohoku University, Sendai 980-8578, Japan 2Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama 35487, USA 3Physics Department, University of California at Berkeley and Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA 4W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125, USA 5Physics Department, Drexel University, Philadelphia, Pennsylvania 19104, USA 6Department of Physics and Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA 7Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA 8Physics Department, University of New Mexico, Albuquerque, New Mexico 87131, USA 9Physics Department, Stanford University, Stanford, California 94305, USA 10Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA 11Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA and Physics Departments at Duke University, North Carolina State University, and the University of North Carolina at Chapel Hill 12Institute of High Energy Physics, Beijing 100039, People's Republic of China 13CEN Bordeaux-Gradignan, IN2P3-CNRS and University Boreaux I, F-33175 Gradignan Cedex, France PASCOS '04

3. Introduction to reactor measurement KamLAND ne Nuclear Reactor L PASCOS '04

4. KamLAND Situated to Detect Reactor Anti-neutrinos Kashiwazaki KamLAND Takahama Ohi PASCOS '04

5. ne Detecting Anti-neutrinos at KamLAND Delayed Prompt • KamLAND (Kamioka Liquid scintillator Anti-Neutrino Detector) 2.2 MeVg 0.5 MeV e- 0.5 MeV n e+ p p d • Inverse beta decay ne + p → e+ + n • The positron losses its energy then annihilates with an electron • The neutron first thermalizes then captures on a proton with a mean capture time of ~200ms PASCOS '04

6. 1km Overburden The Detector Electronics Hut Steel Sphere PMTs 1325 17” 554 20” 34% coverage 1 kton liquid-scintillator Water Cherenkov outer detector 225 PMTs PASCOS '04

7. Inside the Detector PASCOS '04

8. Determining the Event Vertex (2.5MeV) (1.1MeV) (1.0MeV) PASCOS '04

9. τ=29.1ms Q=13.4MeV 12B 12N τ=15.9ms Q=17.3MeV μ Tagged Cosmogenics used as Calibration Device PASCOS '04

10. Fraction of volume used verifiedusing μ-produced 12B/12N and n Neutrons 12B/12N PASCOS '04

11. Energy Calibration Using g Sources and 12B/12N n-p n-12C 68Ge 60Co 65Zn • Includes Birks law, Cherenkov light to obtain constants for γ and e–type depositions PASCOS '04

12. Selecting Electron Anti-neutrinos • Rprompt, Rdelayed < 5.5m • ΔR < 2m • 0.5μs < ΔT < 1ms • 1.8MeV < Edelayed < 2.6MeV • 2.6MeV < Eprompt < 8.5MeV • 89.8% tagging efficiency • 33% increase in volume Delayed Prompt 2.2 MeVg 0.5 MeV 0.5 MeV e+ PASCOS '04

13. Japan Nuclear Reactor Scandal PASCOS '04

14. 2003 saw a substantial dip in reactor anti-neutrino flux PASCOS '04

15. Good correlation with reactor flux Fit constrained through known background c2/dof=2.1/4 No oscillation expected 90% CL PASCOS '04

16. Energy spectrum shows distortion • Best fit c2/dof=18.3/18 (goodness of fit is 42%) • Fit to rescaled reactor spectrum c2/dof=43.4/19 (excluded at 99.89% CL) PASCOS '04

17. Oscillations with L/E KamLAND sees reactor neutrinos from different distances Hypothetical oscillation curve for single reactor distance PASCOS '04

18. Alternative neutrino propagation models • Decay* excluded at 95% CL • Decoherence† excluded at 94% CL *V.Barger et al. Phys. Rev. Lett., 82(1999) 2640 †E.Lisi et al. Phys. Rev. Lett., 85 (2000) 1166 PASCOS '04

19. Two flavor rate and shape analysis • LMA2 excluded at 99.6% CL • Best fit • Dm2=8.3×10-5eV2 • sin22q=0.83 • LMA0 excluded at 94% CL PASCOS '04

20. Improvement since first result New Result Previous Result PASCOS '04

21. Combined solar and KamLAND two flavor result PASCOS '04

22. Prospects • Measure the global concentration of U and Th in the Earth • Solar anti-neutrinos • Solar neutrinos • Exotic nucleon decay modes • Observe supernova neutrinos Geo Signal Reactor Signal PASCOS '04