Adamson, P.Andreopoulos, C.Auty, D. J.Ayres, D. S.Backhouse, C.Barr, G.Bishai, M.Blake, A.Bock, G. J.Boehnlein, D. J.Bogert, D.Cavanaugh, S.Cherdack, D.Childress, S.Choudhary, B. C.Coelho, J. A. B.Coleman, S. J.Corwin, L.Cronin-Hennessy, D.Danko, I. Z.de Jong, J. K.Devenish, N. E.Diwan, M. V.Dorman, M.Escobar, C. O.Evans, J. J.Falk, E.Feldman, GaryFrohne, M. V.Gallagher, H. R.Gomes, R. A.Goodman, M. C.Gouffon, P.Graf, N.Gran, R.Grant, N.Grzelak, K.Habig, A.Harris, D.Hartnell, J.Hatcher, R.Himmel, A.Holin, A.Howcroft, C.Huang, X.Hylen, J.Ilic, J.Irwin, G. M.Isvan, Z.Jaffe, D. E.James, C.Jensen, D.Kafka, T.Kasahara, S. M. S.Koizumi, G.Kopp, S.Kordosky, M.Kreymer, A.Lang, K.Lefeuvre, G.Ling, J.Litchfield, P. J.Loiacono, L.Lucas, P.Mann, W. A.Marshak, M. L.Mayer, N.McGowan, A. M.Mehdiyev, R.Meier, J. R.Messier, M. D.Miller, W. H.Mishra, S. R.Mitchell, J.Moore, C. D.Morfín, J.Mualem, L.Mufson, S.Musser, J.Naples, D.Nelson, J. K.Newman, H. B.Nichol, R. J.Nicholls, T. C.Nowak, J. A.Ochoa-Ricoux, J. P.Oliver, W. P.Orchanian, M.Ospanov, R.Paley, J.Patterson, R. B.Pawloski, G.Pearce, G. F.Petyt, D. A.Phan-Budd, S.Plunkett, R. K.Qiu, X.Ratchford, J.Raufer, T. M.Rebel, B.Rodrigues, P. A.Rosenfeld, C.Rubin, H. A.Sanchez, M. C.Schneps, J.Schreiner, P.Shanahan, P.Sousa, A.Stamoulis, P.Strait, M.Tagg, N.Talaga, R. L.Tetteh-Lartey, E.Thomas, J.Thomson, M. A.Tinti, G.Toner, R.Tzanakos, G.Urheim, J.Vahle, P.Viren, B.Weber, A.Webb, R. C.White, C.Whitehead, L.Wojcicki, S. G.Yang, T.Zwaska, R.2016-09-132011Adamson, P., C. Andreopoulos, D. J. Auty, D. S. Ayres, C. Backhouse, G. Barr, M. Bishai, et al. 2011. “First Direct Observation of Muon Antineutrino Disappearance.” Physical Review Letters 107 (2) (July). doi:10.1103/physrevlett.107.021801.0031-9007http://nrs.harvard.edu/urn-3:HUL.InstRepos:28440203This 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 |Δm⎯⎯⎯2|=[3.36+0.46−0.40(stat)±0.06(syst)]×10−3  eV2, sin2(2θ⎯⎯)=0.86+0.11−0.12(stat)±0.01(syst). The MINOS νμ and ν⎯⎯μ measurements are consistent at the 2.0% confidence level, assuming identical underlying oscillation parameters.en-USantineutrino/mu: secondary beamMINOSantineutrino nucleon: interactioncharged currentneutrino: oscillationfar detectorantineutrino/mu: energy spectrumantineutrino: mass differenceantineutrino: mixing angleexperimental resultsJournal Article2016-09-1310.1103/PhysRevLett.107.021801