Phys. Rev. Lett.
90,
021802
(2003)
[6 pages]
First Results from KamLAND: Evidence for Reactor Antineutrino Disappearance
K. Eguchi et al. KamLAND Collaboration
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K. Eguchi1, S. Enomoto1, K. Furuno1, J. Goldman1, H. Hanada1, H. Ikeda1, K. Ikeda1, K. Inoue1, K. Ishihara1, W. Itoh1, T. Iwamoto1, T. Kawaguchi1, T. Kawashima1, H. Kinoshita1, Y. Kishimoto1, M. Koga1, Y. Koseki1, T. Maeda1, T. Mitsui1, M. Motoki1, K. Nakajima1, M. Nakajima1, T. Nakajima1, H. Ogawa1, K. Owada1, T. Sakabe1, I. Shimizu1, J. Shirai1, F. Suekane1, A. Suzuki1, K. Tada1, O. Tajima1, T. Takayama1, K. Tamae1, H. Watanabe1, J. Busenitz2, Z. Djurcic2, 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, K. M. Heeger3, K. T. Lesko3, K.-B. Luk3, H. Murayama3, D. R. Nygren3, C. E. Okada3, A. W. P. Poon3, H. M. Steiner3, L. A. Winslow3, G. A. Horton-Smith4, R. D. McKeown4, J. Ritter4, B. Tipton4, 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, M. Murakami7, R. C. Svoboda7, B. D. Dieterle8, M. DiMauro8, J. Detwiler9, G. Gratta9, K. Ishii9, N. Tolich9, Y. Uchida9, M. Batygov10, W. Bugg10, H. Cohn10, Y. Efremenko10, Y. Kamyshkov10, A. Kozlov10, Y. Nakamura10, L. De Braeckeleer11, C. R. Gould11, H. J. Karwowski11, D. M. Markoff11, J. A. Messimore11, K. Nakamura11, R. M. Rohm11, W. Tornow11, A. R. Young11, and Y.-F. Wang12 (KamLAND Collaboration)
1Research Center for Neutrino Science, Tohoku University, Sendai 980-8578, Japan
2Department of Physics and Astronomy, University of Alabama, Tuscaloosa, Alabama 35487
3Physics Department, University of California at Berkeley and Lawrence Berkeley National Laboratory, Berkeley, California 94720
4W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125
5Physics Department, Drexel University, Philadelphia, Pennsylvania 19104
6Department of Physics and Astronomy, University of Hawaii at Manoa, Honolulu, Hawaii 96822
7Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803
8Physics Department, University of New Mexico, Albuquerque, New Mexico 87131
9Physics Department, Stanford University, Stanford, California 94305
10Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996
11Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 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
Received 6 December 2002; published 17 January 2003
KamLAND has measured the flux of ν̅ e’s from distant nuclear reactors. We find fewer ν̅ e events than expected from standard assumptions about ν̅ e propagation at the 99.95% C.L. In a 162 ton·yr exposure the ratio of the observed inverse β-decay events to the expected number without ν̅ e disappearance is 0.611±0.085(stat)±0.041(syst) for ν̅ e energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the “large mixing angle” region are excluded.
© 2003 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.90.021802
DOI:
10.1103/PhysRevLett.90.021802
PACS:
14.60.Pq, 26.65.+t, 28.50.Hw, 91.65.Dt
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