Measurement of the neutrino mixing angle $\theta_{23}$ in NOvA

• Main Authors: The NOvA Collaboration, Adamson, P, Ambrose, D, Antoshkin, A, Augsten, K, Backhouse, C, Bending, S, Bernstein, R, Bhuyan, B, Brown, J, Buchanan, N, Bychkov, V, Campbell, M, Catano-Mur, E, Childress, S, Chowdhury, B, Coan, T. E, Coelho, J. A. B, Colo, M, Cooper, J, Cremonesi, L, Davies, G. S, Davies, J. P, Ding, P, Djurcic, Z, Dukes, E. C, Duyang, H, Edayath, S, Feldman, G. J, Gabrielyan, M, Gomes, R. A, Group, R, Grover, D, Hatcher, R, Holin, A, Hylen, J, Judah, M, Kafka, G. K, Kasahara, S. M. S, Kasetti, S, Keloth, R, Kotelnikov, S, Kurbanov, S, Lee, W. M, Lozier, J, Luchuk, S, Magill, S, Mann, W. A, Matveev, V, Méndez, D. P, Messier, M. D, Meyer, H, Miller, W. H, Mohanta, R, Moren, A, Mualem, L, Murphy, R, Musser, J, Nelson, J. K, Nichol, R, Niner, E, Nosek, T, Oksuzian, Y, Patterson, R. B, Pawloski, G, Petti, R, Phan-Budd, S, Poling, R, Principato, C, Psihas, F, Radovic, A, Rameika, R. A, Rebel, B, Rocco, D, Ryabov, V, Sachdev, K, Samoylov, O, Schroeter, R, Shanahan, P, Sheshukov, A, Singh, J, Singh, V, Smolik, J, Solomey, N, Song, E, Soustruznik, K, Strait, M, Suter, L, Talaga, R. L, Tas, P, Thomas, J, Tognini, S. C, Tripathi, J, Vasel, J, Vinton, L, Vrba, T, Wang, B, Whittington, D, Yadav, N, Zalesak, J
• Format: Journal Article
• Language: English
• Published: 20.01.2017
• Subjects: Physics - High Energy Physics - Experiment
• DOI: 10.48550/arxiv.1701.05891

Phys. Rev. Lett. 118, 151802 (2017) This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of $6.05\times10^{20}$ protons-on-target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal mixing ($\theta_{23} = \pi/4$). Assuming the normal mass hierarchy, we find $\Delta m^2 = (2.67 \pm 0.11)\times 10^{-3}$ eV$^2$ and $\sin^2 \theta_{23}$ at the two statistically degenerate values $0.404^{+0.030}_{-0.022}$ and $0.624^{+0.022}_{-0.030}$, both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6 $\sigma$ significance.