Dual-baseline search for active-to-sterile neutrino oscillations in NOvA

Abstract

We report a search for neutrino oscillations to sterile neutrinos under a model with three active and one sterile neutrinos (3+1 model). This analysis uses the NOvA detectors exposed to the NuMI beam, running in neutrino mode. The data exposure, 13.6×1020 protons on target, doubles that previously analyzed by NOvA, and the analysis is the first to use 𝜈𝜇 charged-current interactions in conjunction with neutral-current interactions. Neutrino samples in the near and far detectors are fitted simultaneously, enabling the search to be carried out over a Δ⁢𝑚2 41 range extending 2 (3) orders of magnitude above (below) 1 eV2. NOvA finds no evidence for active-to-sterile neutrino oscillations under the 3+1 model at 90% confidence level. New limits are reported in multiple regions of parameter space, excluding some regions currently allowed by IceCube at 90% confidence level. We additionally set the most stringent limits for anomalous 𝜈𝜏 appearance for Δ⁢𝑚2 41≤3 eV2.