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 Shimizu; Y 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; KamLAND Collaboration

doi:10.1103/PhysRevLett.100.221803

Precision measurement of neutrino oscillation parameters with KamLAND

Phys Rev Lett. 2008 Jun 6;100(22):221803. doi: 10.1103/PhysRevLett.100.221803. Epub 2008 Jun 5.

Authors

S Abe¹, 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 Shimizu, Y 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; KamLAND Collaboration

Affiliation

¹ Research Center for Neutrino Science, Tohoku University, Sendai 980-8578, Japan.

PMID: 18643415
DOI: 10.1103/PhysRevLett.100.221803

Abstract

The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44 x 10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor nu[over]e energy spectrum is now rejected at >5sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Deltam21(2)=7.58(-0.13)(+0.14)(stat) -0.15+0.15(syst) x 10(-5) eV2 and tan2theta12=0.56(-0.07)+0.10(stat) -0.06+0.10(syst). Local Deltachi2 minima at higher and lower Deltam21(2) are disfavored at >4sigma. Combining with solar neutrino data, we obtain Deltam21(2)=7.59(-0.21)+0.21 x 10(-5) eV2 and tan2theta12=0.47(-0.05)+0.06.