2023-05-222023-05-222021ACERO, M. A. et al. Search for active-sterile antineutrino mixing using neutral-current interactions with the NOvA experiment. Physical Review Letters Washington, v. 127, e201801, 2021. DOI: 10.1103/PhysRevLett.127.201801. Disponível em: https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.127.201801. Acesso em: 16 maio 2023.0031-9007e- 1079-7114http://repositorio.bc.ufg.br/handle/ri/22600This Letter reports results from the first long-baseline search for sterile antineutrinos mixing in an accelerator-based antineutrino-dominated beam. The rate of neutral-current interactions in the two NOvA detectors, at distances of 1 and 810 km from the beam source, is analyzed using an exposure of 12.51 × 1020 protons-on-target from the NuMI beam at Fermilab running in antineutrino mode. A total of 121 of neutral-current candidates are observed at the far detector, compared to a prediction of 122 11ðstat:Þ 15ðsyst:Þ assuming mixing only between three active flavors. No evidence for ¯νμ → ¯νs oscillation is observed. Interpreting this result within a 3 þ 1 model, constraints are placed on the mixing angles θ24 < 25° and θ34 < 32° at the 90% C.L. for 0.05 eV2 ≤ Δm2 41 ≤ 0.5 eV2, the range of mass splittings that produces no significant oscillations at the near detector. These are the first 3 þ 1 confidence limits set using long-baseline accelerator antineutrinos.engAcesso AbertoArtigo10.1103/PhysRevLett.127.201801