PT Journal
AU T2K Collaboration (Abe, Kea
   Cervera-Villanueva, A
   Escudero, L
   Izmaylov, A
   Monfregola, L
   Sorel, M
   Stamoulis, P
TI Precise Measurement of the Neutrino Mixing Parameter theta(23) from Muon Neutrino Disappearance in an Off-Axis Beam
SO Physical Review Letters
JI Phys. Rev. Lett.
PY 2014
BP 181801
EP 8pp
VL 112
IS 18
DI 10.1103/PhysRevLett.112.181801
LA English
AB 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. The 68% confidence limit on sin(2)(theta(23)) is 0.514(-0.056)(+0.055) (0.511 +/- 0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Delta m(32)(2) = (2.51 +/- 0.10) x 10(-3) eV(2)/c(4) (inverted hierarchy: Delta m(13)(2) = (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.
ER