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

TL;DR

This paper reports on a search for sterile neutrinos using neutral-current interactions in the MINOS experiment, setting limits on active to sterile neutrino oscillations based on observed event rates.

Contribution

It provides new constraints on active to sterile neutrino mixing by analyzing neutral-current interactions in a long-baseline experiment.

Findings

Observed 802 neutral-current events in the Far Detector.

Expected 754±28(stat.)±37(syst.) events assuming only active neutrino oscillations.

The fraction of muon neutrinos transitioning to sterile neutrinos is less than 22% at 90% confidence level.

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 $\nu_s$ is found to be less than 22% at the 90% C.L.