We present results of a study of neutrino oscillation based on a 766 ton/year exposure of KamLAND to reactor antineutrinos. We observe 258 nu (e) candidate events with energies above 3.4 MeV compared to 365.2+/-23.7 events expected in the absence of neutrino oscillation. Accounting for 17.8+/-7.3 expected background events, the statistical significance for reactor nu (e) disappearance is 99.998%. The observed energy spectrum disagrees with the expected spectral shape in the absence of neutrino oscillation at 99.6% significance and prefers the distortion expected from nu (e) oscillation effects. A two-neutrino oscillation analysis of the KamLAND data gives Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2). A global analysis of data from KamLAND and solar-neutrino experiments yields Deltam(2)=7.9(+0.6)(-0.5)x10(-5) eV(2) and tan((2)theta=0.40(+0.10)(-0.07), the most precise determination to date.

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The recent long-term shutdown of Japanese nuclear reactors has resulted in a significantly reduced reactor νe flux at KamLAND. This running condition provides a unique opportunity to confirm and constrain backgrounds for the reactor νe oscillation analysis. The data set also has improved sensitivity for other νe signals, in particular νe's produced in β-decays from 238 U and 232 Th within the Earth's interior, whose energy spectrum overlaps with that of reactor νe'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 tan 2 θ12 = 0.436

We report on measurements of neutrino oscillation using data from the T2K long-baseline neutrino experiment collected between 2010 and 2013. In an analysis of muon neutrino disappearance alone, we find the following estimates and 68% confidence intervals for the two possible mass hierarchies: normal hierarchy∶ sin 2 θ 23 ¼ 0.514 þ0.055 −0.056 and Δm 2 32 ¼ ð2.51 AE 0.10Þ × 10 −3 eV 2 =c 4 and inverted hierarchy∶ sin 2 θ 23 ¼ 0.511 AE 0.055 and Δm 2 13 ¼ ð2.48 AE 0.10Þ × 10 −3 eV 2 =c 4 . The analysis accounts for multinucleon mechanisms in neutrino interactions which were found to introduce negligible bias. We describe our first analyses that combine measurements of muon neutrino disappearance and electron neutrino appearance to estimate four oscillation parameters, jΔm 2 j, sin 2 θ 23 , sin 2 θ 13 , δ CP , and the mass hierarchy. Frequentist and Bayesian intervals are presented for combinations of these parameters, with and without including recent reactor measurements. At 90% confidence level and including reactor measurements, we exclude the region δ CP ¼ ½0.15; 0.83 π for normal hierarchy and δ CP ¼ ½−0.08; 1.09 π for inverted hierarchy. The T2K and reactor data weakly favor the normal hierarchy with a Bayes factor of 2.2. The most probable values and 68% one-dimensional credible intervals for the other oscillation parameters, when reactor data are included, are sin 2 θ 23 ¼ 0.528 þ0.055 −0.038 and jΔm 2 32 j ¼ ð2.51 AE 0.11Þ × 10 −3 eV 2 =c 4 .