# Precise Measurement of the Neutrino Mixing Parameter \theta_{23} from Muon Neutrino Disappearance in an Off-axis Beam

Abstract : New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter theta_{23}. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57 x 10^{20} protons on target, T2K has fit the energy-dependent nu_mu oscillation probability to determine oscillation parameters. Marginalizing over the values of other oscillation parameters yields sin^2 (theta_{23}) = 0.514 +0.055/-0.056 (0.511 +- 0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Delta m^2_{32} = 2.51 +- 0.10 x 10^{-3} eV^2/c^4 (inverted hierarchy: Delta m^2_{13} = 2.48 +- 0.10 x 10^{-3} eV^2/c^4). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00956637
Contributor : Sylvie Flores <>
Submitted on : Friday, March 7, 2014 - 8:25:08 AM
Last modification on : Friday, September 10, 2021 - 1:50:10 PM

### Citation

K. Abe, J. Adam, H. Aihara, T. Akiri, C. Andreopoulos, et al.. Precise Measurement of the Neutrino Mixing Parameter \theta_{23} from Muon Neutrino Disappearance in an Off-axis Beam. Physical Review Letters, American Physical Society, 2014, 112, pp.181801. ⟨10.1103/PhysRevLett.112.181801⟩. ⟨in2p3-00956637⟩

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