The NOvA experiment has seen a 4.4σ signal of ⊽ e appearance in a 2 GeV⊽μ beam at a distance of 810 km. Using 12.33×1020 protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 ⊽μ→⊽e candidates with a background of 10.3 and 102⊽μ→⊽μ candidates. This new antineutrino data are combined with neutrino data to measure the parameters |Δm 2 32 | = 2.48 +0.11 -0.06 x 10 -3 eV2 / c4 and sin2 θ23 in the ranges from (0.53- 0.60) and (0.45-0.48) in the normal neutrino mass hierarchy. The data exclude most values near δ CP = π / 2 for the inverted mass hierarchy by more than 3 σ and favor the normal neutrino mass hierarchy by 1.9σ and θ23 values in the upper octant by 1.6σ .
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Published in Physical Review Letters, Volume 123, Issue 15, 2019, pages 151803-.
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Acero, M. A., Adamson, P., Aliaga, L., T. Alion, V. Allakhverdian, S. Altakarli, N. Anfimov, A. Antoshkin, A. Aurisano, Back, A., C. Backhouse, Baird, M., N. Balashov, Baldi, P., B. Bambah, Bashar, S., Bays, K., Bending, S., Bernstein, R. H., & Bhatnagar, V. (2019). First measurement of neutrino oscillation parameters using neutrinos and antineutrinos by NOvA. Physical Review Letters, 123(15). https://doi.org/10.1103/physrevlett.123.151803