First Direct Observation of Muon Antineutrino Disappearance Academic Article uri icon


  • This Letter reports the first direct observation of muon antineutrino disappearance. The MINOS experiment has taken data with an accelerator beam optimized for ν(μ) production, accumulating an exposure of 1.71 × 10²⁰ protons on target. In the Far Detector, 97 charged current ν(μ) events are observed. The no-oscillation hypothesis predicts 156 events and is excluded at 6.3σ. The best fit to oscillation yields |Δm²| = [3.36(-0.40)(+0.46)(stat) ± 0.06(syst)] × 10⁻³ eV², sin²(2θ) = 0.86(-0.12)(+0.11)(stat) ± 0.01(syst). The MINOS ν(μ) and ν(μ) measurements are consistent at the 2.0% confidence level, assuming identical underlying oscillation parameters.

author list (cited authors)

  • Adamson, P., Andreopoulos, C., Auty, D. J., Ayres, D. S., Backhouse, C., Barr, G., ... Zwaska, R.

publication date

  • January 1, 2011 11:11 AM


  • Minos Collaboration