Reactor on-off antineutrino measurement with KamLAND

A. Gando, Y. Gando, H. Hanakago, H. Ikeda, K. Inoue, K. Ishidoshiro, H. Ishikawa, M. Koga, R. Matsuda, S. Matsuda, T. Mitsui, D. Motoki, K. Nakamura, A. Obata, A. Oki, Y. Oki, M. Otani, I. Shimizu, J. Shirai, A. SuzukiY. Takemoto, K. Tamae, K. Ueshima, H. Watanabe, B. D. Xu, S. Yamada, Y. Yamauchi, H. Yoshida, A. Kozlov, S. Yoshida, A. Piepke, T. I. Banks, B. K. Fujikawa, K. Han, T. O'Donnell, B. E. Berger, J. G. Learned, S. Matsuno, M. Sakai, Y. Efremenko, H. J. Karwowski, D. M. Markoff, W. Tornow, J. A. Detwiler, S. Enomoto, M. P. Decowski

研究成果: Article査読

236 被引用数 (Scopus)


The recent long-term shutdown of Japanese nuclear reactors has resulted in a significantly reduced reactor ν̄e flux at KamLAND. This running condition provides a unique opportunity to confirm and constrain backgrounds for the reactor ν̄e oscillation analysis. The data set also has improved sensitivity for other ν̄e signals, in particular ν̄e's produced in β-decays from U238 and Th232 within the Earth's interior, whose energy spectrum overlaps with that of reactor ν̄e's. Including constraints on θ13 from accelerator and short-baseline reactor neutrino experiments, a combined three-flavor analysis of solar and KamLAND data gives fit values for the oscillation parameters of tan12=0.436-0.025+0.029, Δm212=7.53-0.18+0.18×10-5 eV2, and sin13=0.023-0.002+0.002. Assuming a chondritic Th/U mass ratio, we obtain 116-27+28 ν̄e events from U238 and Th232, corresponding to a geo ν̄e flux of 3.4-0.8+0.8×106 cm-2 s-1 at the KamLAND location. We evaluate various bulk silicate Earth composition models using the observed geo ν̄e rate.

ジャーナルPhysical Review D - Particles, Fields, Gravitation and Cosmology
出版ステータスPublished - 2013 8月 2

ASJC Scopus subject areas

  • 核物理学および高エネルギー物理学
  • 物理学および天文学(その他)


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