Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6 × 10²⁰protons on target

Authors

K. Abe, The University of Tokyo
J. Adam, Stony Brook University
H. Aihara, The University of Tokyo
T. Akiri, Duke University
C. Andreopoulos, University of Liverpool
S. Aoki, Kobe University
A. Ariga, University of Bern
S. Assylbekov, Colorado State University
D. Autiero, Université Claude Bernard Lyon 1
M. Barbi, University of Regina
G. J. Barker, University of Warwick
G. Barr, University of Oxford
P. Bartet-Friburg, Université de Paris
M. Bass, Colorado State University
M. Batkiewicz, Henryk Niewodniczanski Institute of Nuclear Physics of the Polish Academy of Sciences
F. Bay, ETH Zürich
V. Berardi, Politecnico di Bari
B. E. Berger, Colorado State University
S. Berkman, The University of British Columbia
S. Bhadra, York University
F. D.M. Blaszczyk, Boston University
A. Blondel, Université de Genève
S. Bolognesi, Institut de Recherche sur les Lois Fondamentales de l'Univers
S. Bordoni, Institut de Física d'Altes Energies, Bellaterra
S. B. Boyd, University of Warwick
D. Brailsford, Imperial College London
A. Bravar, Université de Genève
C. Bronner, The University of Tokyo

Document Type

Article

Publication Date

4-29-2015

Abstract

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: sin2θ23= 0.514-0.056+0.055and Δm322= (2.51 ± 0.10) × 10-3eV2/c4and inverted hierarchy: sin2θ23= 0.511 ± 0.055 and Δm132= (2.48 ± 0.10) × 10-3eV2/c4. 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, |Δm2|, sin2θ23, sin2θ13, δCP, 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 δCP= [0.15; 0.83]π for normal hierarchy and δCP= [-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 sin2θ23= 0.528-0.038+0.055and |Δm322| = (2.51 ± 0.11) × 10-3eV2/c4.

Publication Source (Journal or Book title)

Physical Review D - Particles, Fields, Gravitation and Cosmology

Recommended Citation

Abe, K., Adam, J., Aihara, H., Akiri, T., Andreopoulos, C., Aoki, S., Ariga, A., Assylbekov, S., Autiero, D., Barbi, M., Barker, G., Barr, G., Bartet-Friburg, P., Bass, M., Batkiewicz, M., Bay, F., Berardi, V., Berger, B., Berkman, S., Bhadra, S., Blaszczyk, F., Blondel, A., Bolognesi, S., Bordoni, S., Boyd, S., Brailsford, D., Bravar, A., & Bronner, C. (2015). Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6 × 10²⁰protons on target. Physical Review D - Particles, Fields, Gravitation and Cosmology, 91 (7) https://doi.org/10.1103/PhysRevD.91.072010