Improved measurement of neutrino oscillation parameters by the NOvA experiment

Resumo

We present new νμ → νe, νμ → νμ, ¯νμ → ¯νe, and ¯νμ → ¯νμ 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, ¯νe, and ¯νμ 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 Δm2 32 ¼ ð2.41 0.07Þ × 10−3 eV2 and sin2 θ23 ¼ 0.57þ0.03 −0.04 . The data disfavor combinations of oscillation parameters that give rise to a large asymmetry in the rates of νe and ¯νe appearance. This includes values of the charge parity symmetry (CP) violating phase in the vicinity of δCP ¼ π=2 which are excluded by > 3σ for the inverted mass ordering, and values around δCP ¼ 3π=2 in the normal ordering which are disfavored at 2σ confidence.

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Citação

ACERO, M. A. et al. Improved measurement of neutrino oscillation parameters by the NOvA experiment. Physical Review D, Washington, v. 106, n. 3, e032004, 2022. DOI: 10.1103/PhysRevD.106.032004. Disponível em: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.106.032004. Acesso em: 16 maio 2023.