Search for active neutrino disappearance using neutral-current interactions in the MINOS long-baseline experiment

TL;DR

This study compares neutral-current neutrino interaction rates at two locations in the MINOS experiment to search for sterile neutrino mixing, finding no significant depletion and setting limits on sterile neutrino participation.

Contribution

First detailed comparison of neutral-current neutrino interactions at two sites, providing new limits on sterile neutrino mixing in the MINOS experiment.

Findings

No anomalous depletion observed in neutral-current spectrum.

Limits set on muon neutrino oscillation to sterile neutrinos below 0.68 at 90% CL.

Possible contribution from electron neutrino appearance considered.

Abstract

We report the first detailed comparisons of the rates and spectra of neutral-current neutrino interactions at two widely separated locations. A depletion in the rate at the far site would indicate mixing between muon neutirnos and a sterile particle. No anomalous depletion in the reconstructed energy spectrum is observed. Assuming oscillations occur at a single mass-squared splitting, a fit to the neutral- and charged-current energy spectra limits the fraction of muon neutrino oscillating to a sterile neutrino to be below 0.68 at 90% confidence level. A less stringent limit due to a possible contribution to the measured neutral-current event rate at the far site from electron neutrino appearance at the current experimental limit is also presented.