Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Authors

K. Abe, The University of Tokyo
R. Akutsu, The University of Tokyo
A. Ali, Kyoto University
C. Alt, ETH Zürich
C. Andreopoulos, University of Liverpool
L. Anthony, University of Liverpool
M. Antonova, Universitat de València
S. Aoki, Kobe University
A. Ariga, University of Bern
Y. Asada, Yokohama National University
Y. Ashida, Kyoto University
E. T. Atkin, Imperial College London
Y. Awataguchi, Tokyo Metropolitan University
S. Ban, Kyoto University
M. Barbi, University of Regina
G. J. Barker, Faculty of Science, Engineering and Medicine
G. Barr, University of Oxford
D. Barrow, University of Oxford
C. Barry, University of Liverpool
M. Batkiewicz-Kwasniak, Henryk Niewodniczanski Institute of Nuclear Physics of the Polish Academy of Sciences
A. Beloshapkin, Institute for Nuclear Research of the Russian Academy of Sciences
F. Bench, University of Liverpool
V. Berardi, Istituto Nazionale di Fisica Nucleare, Sezione di Bari
S. Berkman, The University of British Columbia
L. Berns, Tokyo Institute of Technology
S. Bhadra, York University
S. Bienstock, Sorbonne Universite
A. Blondel, Université de Genève

Document Type

Article

Publication Date

4-24-2020

Abstract

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

Publication Source (Journal or Book title)

Physical Review Letters

Recommended Citation

Abe, K., Akutsu, R., Ali, A., Alt, C., Andreopoulos, C., Anthony, L., Antonova, M., Aoki, S., Ariga, A., Asada, Y., Ashida, Y., Atkin, E., Awataguchi, Y., Ban, S., Barbi, M., Barker, G., Barr, G., Barrow, D., Barry, C., Batkiewicz-Kwasniak, M., Beloshapkin, A., Bench, F., Berardi, V., Berkman, S., Berns, L., Bhadra, S., Bienstock, S., & Blondel, A. (2020). Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam. Physical Review Letters, 124 (16) https://doi.org/10.1103/PhysRevLett.124.161802