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Improved measurement of neutrino oscillation parameters by the NOvA experiment

Publication at Faculty of Mathematics and Physics |
2022

Abstract

We present new nu(mu) -> nu(e), nu(mu) -> nu(mu), (nu) over bar (mu) -> (nu) over bar (e), and (nu) over bar (mu) -> (nu) over bar (mu) 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 nu(e), nu(mu), (nu) over bar (e), and (nu) over bar (mu), 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 theta(23) mixing angle, with Delta m(32)(2) = (2.41 +/- 0.07) x 10(-3) eV(2) and sin(2)theta(23) = 0.57(-0.04)(+0.03). The data disfavor combinations of oscillation parameters that give rise to a large asymmetry in the rates of nu(e) and (nu) over bar (e) appearance.

This includes values of the charge parity symmetry (CP) violating phase in the vicinity of delta(CP) = pi/2 which arc excluded by > 3 sigma for the inverted mass ordering, and values around delta(CP) = 3 pi/2 in the normal ordering which are disfavored at 2 sigma confidence.