Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

• Published in: Physical review letters 2018-10, Vol.121 (17), p.171802-171802
• Main Authors: Abe, K, Akutsu, R, Ali, A, Amey, J, Andreopoulos, C, Anthony, L, Antonova, M, Aoki, S, Ariga, A, Ashida, Y, Azuma, Y, Ban, S, Barbi, M, Barker, G J, Barr, G, Barry, C, Batkiewicz, M, Bench, F, Berardi, V, Berkman, S, Berner, R M, Berns, L, Bhadra, S, Bienstock, S, Blondel, A, Bolognesi, S, Bourguille, B, Boyd, S B, Brailsford, D, Bravar, A, Bronner, C, Buizza Avanzini, M, Calcutt, J, Campbell, T, Cao, S, Cartwright, S L, Catanesi, M G, Cervera, A, Chappell, A, Checchia, C, Cherdack, D, Chikuma, N, Christodoulou, G, Coleman, J, Collazuol, G, Coplowe, D, Cudd, A, Dabrowska, A, De Rosa, G, Dealtry, T, Denner, P F, Dennis, S R, Densham, C, Di Lodovico, F, Dokania, N, Dolan, S, Drapier, O, Duffy, K E, Dumarchez, J, Dunne, P, Emery-Schrenk, S, Ereditato, A, Fernandez, P, Feusels, T, Finch, A J, Fiorentini, G A, Fiorillo, G, Francois, C, Friend, M, Fujii, Y, Fujita, R, Fukuda, D, Fukuda, Y, Gameil, K, Giganti, C, Gizzarelli, F, Golan, T, Gonin, M, Hadley, D R, Haegel, L, Haigh, J T, Hamacher-Baumann, P, Hansen, D, Harada, J, Hartz, M, Hasegawa, T, Hastings, N C, Hayashino, T, Hayato, Y, Hiramoto, A, Hogan, M, Holeczek, J, Hosomi, F, Ichikawa, A K, Ikeda, M, Imber, J, Inoue, T, Intonti, R A, Ishida, T, Ishii, T
• Format: Article
• Language: English
• ISSN: 1079-7114
• DOI: 10.1103/PhysRevLett.121.171802

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.