Search for the disappearance of muon antineutrinos in the NuMI neutrino beam

TL;DR

This paper presents constraints on muon antineutrino oscillation parameters using the MINOS detectors, measuring the antineutrino component of the NuMI beam and setting limits on the oscillation parameters at 90% confidence level.

Contribution

First measurement of muon antineutrino oscillation parameters using the NuMI beam with constraints derived from MINOS detector data.

Findings

130 observed events vs. 136.4 expected without oscillations

Upper limit on |dm2bar| < 3.37 x 10^-3 eV^2 at 90% CL

Constraints consistent with previous measurements of neutrino oscillations

Abstract

We report constraints on antineutrino oscillation parameters that were obtained by using the two MINOS detectors to measure the 7% muon antineutrino component of the NuMI neutrino beam. In the Far Detector, we select 130 events in the charged-current muon antineutrino sample, compared to a prediction of 136.4 +/- 11.7(stat) ^{+10.2}_{-8.9}(syst) events under the assumption |dm2bar|=2.32x10^-3 eV^2, snthetabar=1.0. Assuming no oscillations occur at the Near Detector baseline, a fit to the two-flavor oscillation approximation constrains |dm2bar|<3.37x10^-3 eV^2 at the 90% confidence level with snthetabar=1.0.