Active to sterile neutrino mixing limits from neutral-current interactions in MINOS

TL;DR

Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrinos interactions, from an exposure to the NuMI neutrini beam of 7.07×10(20) protons on target.

Abstract

Results are reported from a search for active to sterile neutrino oscillations in the MINOS long-baseline experiment, based on the observation of neutral-current neutrino interactions, from an exposure to the NuMI neutrino beam of $7.07\times10^{20}$ protons on target. A total of 802 neutral-current event candidates is observed in the Far Detector, compared to an expected number of $754\pm28\rm{(stat.)}\pm{37}\rm{(syst.)}$ for oscillations among three active flavors. The fraction $f_s$ of disappearing \numu that may transition to $ν_s$ is found to be less than 22% at the 90% C.L.

Figures (2)

• Figure 1: Reconstructed energy spectrum of NC-selected events in the ND (solid points) compared to the Monte Carlo prediction (open histogram) shown with [1]$\sigma$ systematic errors (shaded band). Also displayed is the simulation of the background from misidentified CC events (hatched histogram).
• Figure 2: Reconstructed energy spectrum of NC-selected events in the FD (points with statistical errors) compared with predictions for standard three-flavor mixing with and without $\nu_e$ appearance at the MINOS 90% C.L. limit ref:minosnue (dashed and solid lines respectively).