Precision measurement of neutrino oscillation parameters with KamLAND

S. Abe, T. Ebihara, S. Enomoto, K. Furuno, Y. Gando, K. Ichimura, H. Ikeda, K. Inoue, Y. Kibe, Y. Kishimoto, M. Koga, A. Kozlov, Y. Minekawa, T. Mitsui, K. Nakajima, K. Nakajima, K. Nakamura, M. Nakamura, K. Owada, I. ShimizuY. Shimizu, J. Shirai, F. Suekane, A. Suzuki, Y. Takemoto, K. Tamae, A. Terashima, H. Watanabe, E. Yonezawa, S. Yoshida, J. Busenitz, T. Classen, C. Grant, G. Keefer, D. S. Leonard, D. McKee, A. Piepke, M. P. Decowski, J. A. Detwiler, S. J. Freedman, B. K. Fujikawa, F. Gray, E. Guardincerri, L. Hsu, R. Kadel, C. Lendvai, K. B. Luk, H. Murayama, T. O'Donnell, H. M. Steiner, L. A. Winslow, D. A. Dwyer, C. Jillings, C. Mauger, R. D. McKeown, P. Vogel, C. Zhang, B. E. Berger, C. E. Lane, J. Maricic, T. Miletic, M. Batygov, J. G. Learned, S. Matsuno, S. Pakvasa, J. Foster, G. A. Horton-Smith, A. Tang, S. Dazeley, K. E. Downum, G. Gratta, K. Tolich, W. Bugg, Y. Efremenko, Y. Kamyshkov, O. Perevozchikov, H. J. Karwowski, D. M. Markoff, W. Tornow, K. M. Heeger, F. Piquemal, J. S. Ricol

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667 Citations (Scopus)


The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Δm212 and stringent constraints on θ12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44×1032protonyr due to longer livetime and an enlarged fiducial volume. An undistorted reactor ν̄e energy spectrum is now rejected at >5σ. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Δm212=7.58-0.13+0.14(stat)-0.15+0.15(syst)×10-5eV2 and tan 2θ12=0.56-0.07+0.10(stat)-0.06+0.10(syst). Local Δχ2 minima at higher and lower Δm212 are disfavored at >4σ. Combining with solar neutrino data, we obtain Δm212=7.59-0.21+0.21×10-5eV2 and tan 2θ12=0.47-0.05+0.06.

Original languageEnglish
Article number221803
JournalPhysical review letters
Issue number22
Publication statusPublished - 2008 Jun 5

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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