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 D S, McKee D, Piepke A, Decowski M P, Detwiler J A, Freedman S J, Fujikawa B K, Gray F, Guardincerri E, Hsu L, Kadel R, Lendvai C, Luk K-B, Murayama H, O'Donnell T, Steiner H M, Winslow L A, Dwyer D A, Jillings C, Mauger C, McKeown R D, Vogel P, Zhang C, Berger B E, Lane C E, Maricic J, Miletic T, Batygov M, Learned J G, Matsuno S, Pakvasa S, Foster J, Horton-Smith G A, Tang A, Dazeley S, Downum K E, Gratta G, Tolich K, Bugg W, Efremenko Y, Kamyshkov Y, Perevozchikov O, Karwowski H J, Markoff D M, Tornow W, Heeger K M, Piquemal F, Ricol J-S
Research Center for Neutrino Science, Tohoku University, Sendai 980-8578, Japan.
Phys Rev Lett. 2008 Jun 6;100(22):221803. doi: 10.1103/PhysRevLett.100.221803. Epub 2008 Jun 5.
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.
KamLAND实验确定了中微子振荡参数Δm₂₁²的精确值，并对θ₁₂给出了严格限制。由于更长的运行时间和扩大的基准体积，对核反应堆反中微子的曝光量比之前的结果增加了近四倍，达到2.44×10³²质子年。现在，一个未畸变的反应堆ν̅e能谱在大于5σ的水平上被排除。对高于逆β衰变能量阈值的反应堆能谱进行分析，并包括地球中微子，得到的最佳拟合结果为：Δm₂₁² = 7.58（-0.13）（+0.14）（统计） - 0.15 + 0.15（系统）×10⁻⁵ eV²，tan²θ₁₂ = 0.56（-0.07）+0.10（统计） - 0.06 + 0.10（系统）。在更高和更低的Δm₂₁²处的局部Δχ²最小值在大于4σ的水平上不被支持。结合太阳中微子数据，我们得到Δm₂₁² = 7.59（-0.21）+0.21×10⁻⁵ eV²，tan²θ₁₂ = 0.47（-0.05）+0.06。
Zotero 插件