Improved measurement of neutrino oscillation parameters by the NOvA experiment

We present new νμ→νe, νμ→νμ, ν¯μ→ν¯e, and ν¯μ→ν¯μ oscillation measurements by the NOvA experiment, with a 50% increase in neutrino-mode beam exposure over the previously reported results. The additional data, combined with previously published neutrino and antineutrino data, are all analyzed using improved techniques and simulations. A joint fit to the νe, νμ, ν¯e, and ν¯μ candidate samples within the 3-flavor neutrino oscillation framework continues to yield a best-fit point in the normal mass ordering and the upper octant of the θ23 mixing angle, with Δm322=(2.41±0.07)×10-3 eV2 and sin2θ23=0.57-0.04+0.03. The data disfavor combinations of oscillation parameters that give rise to a large asymmetry in the rates of νe and ν¯e appearance. This includes values of the charge parity symmetry (CP) violating phase in the vicinity of δCP=π/2 which are excluded by >3σ for the inverted mass ordering, and values around δCP=3π/2 in the normal ordering which are disfavored at 2σ confidence.