Constraints on θ13 from a three-flavor oscillation analysis of reactor antineutrinos at KamLAND

A. Gando, Y. Gando, K. Ichimura, H. Ikeda, K. Inoue, Y. Kibe, Y. Kishimoto, M. Koga, Y. Minekawa, T. Mitsui, T. Morikawa, N. Nagai, K. Nakajima, K. Nakamura, K. Narita, I. Shimizu, Y. Shimizu, J. Shirai, F. Suekane, A. SuzukiH. Takahashi, N. Takahashi, Y. Takemoto, K. Tamae, H. Watanabe, B. D. Xu, H. Yabumoto, H. Yoshida, S. Yoshida, S. Enomoto, A. Kozlov, H. Murayama, C. Grant, G. Keefer, A. Piepke, T. I. Banks, T. Bloxham, J. A. Detwiler, S. J. Freedman, B. K. Fujikawa, K. Han, R. Kadel, T. O'Donnell, H. M. Steiner, D. A. Dwyer, R. D. McKeown, C. Zhang, B. E. Berger, C. E. Lane, J. Maricic, T. Miletic, M. Batygov, J. G. Learned, S. Matsuno, M. Sakai, G. A. Horton-Smith, K. E. Downum, G. Gratta, Y. Efremenko, O. Perevozchikov, H. J. Karwowski, D. M. Markoff, W. Tornow, K. M. Heeger, M. P. Decowski

Research output: Contribution to journalArticlepeer-review

115 Scopus citations


We present new constraints on the neutrino oscillation parameters Δm212, θ12, and θ13 from a three-flavor analysis of solar and KamLAND data. The KamLAND data set includes data acquired following a radiopurity upgrade and amounts to a total exposure of 3.49×1032 target-proton-year. Under the assumption of CPT invariance, a two-flavor analysis (θ13=0) of the KamLAND and solar data yields the best-fit values tan12=0.444-0.030+0.036 and Δm212=7.50-0.20+0.19×10-5eV2; a three-flavor analysis with θ13 as a free parameter yields the best-fit values tan12=0.452-0.033+0.035, Δm212=7.50-0.20+0.19×10-5eV2, and sin13=0.020-0.016+0.016. This θ13 interval is consistent with other recent work combining the CHOOZ, atmospheric and long-baseline accelerator experiments. We also present a new global θ13 analysis, incorporating the CHOOZ, atmospheric, and accelerator data, which indicates sin13=0.009-0. 007+0.013. A nonzero value is suggested, but only at the 79% C.L.

Original languageEnglish (US)
Article number052002
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number5
StatePublished - Mar 4 2011
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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