First measurement of neutrino oscillation parameters using neutrinos and antineutrinos by NOvA

The NOvA experiment has seen a 4.4σ signal of νₑ appearance in a 2 GeV ν_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 ν_μ→νₑ candidates with a background of 10.3 and 102 ν_μ→ν_μ candidates. This new antineutrino data are combined with neutrino data to measure the parameters |Δm₃₂²|=2.48_-0.06+0.11×10^-3 eV²/c⁴ and sin²θ₂₃ 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 δCP=π/2 for the inverted mass hierarchy by more than 3σ and favor the normal neutrino mass hierarchy by 1.9σ and θ₂₃ values in the upper octant by 1.6σ.