Abe S, Ebihara T, Enomoto S, Furuno K, Gando Y, Ichimura K, Ikeda H, Inoue K, Kibe Y, Kishimoto Y, Koga M, Kozlov A, Minekawa Y, Mitsui T, Nakajima K, Nakajima K, Nakamura K, Nakamura M, Owada K, Shimizu I, Shimizu Y, Shirai J, Suekane F, Suzuki A, Takemoto Y, Tamae K, Terashima A, Watanabe H, Yonezawa E, Yoshida S, Busenitz J, Classen T, Grant C, Keefer G, Leonard DS, McKee D, Piepke A, Decowski MP, Detwiler JA, Freedman SJ, Fujikawa BK, Gray F, Guardincerri E, Hsu L, Kadel R, Lendvai C, Luk KB, Murayama H, O'Donnell T, Steiner HM, Winslow LA, Dwyer DA, Jillings C, Mauger C, McKeown RD, Vogel P, Zhang C, Berger BE, Lane CE, Maricic J, Miletic T, Batygov M, Learned JG, Matsuno S, Pakvasa S, Foster J, Horton-Smith GA, Tang A, Dazeley S, Downum KE, Gratta G, Tolich K, Bugg W, Efremenko Y, Kamyshkov Y, Perevozchikov O, Karwowski HJ, Markoff DM, Tornow W, Heeger KM, Piquemal F, Ricol JS. Precision measurement of neutrino oscillation parameters with KamLAND.
PHYSICAL REVIEW LETTERS 2008;
100:221803. [PMID:
18643415 DOI:
10.1103/physrevlett.100.221803]
[Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Indexed: 05/26/2023]
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.
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