Paper

Measurements of atmospheric neutrinos and antineutrinos in the MINOS Far Detector

Torretta, D, Graf, N, Thomson, M A, Kreymer, A, Walding, J J, Himmel, A, Gran, R, Toner, R, Moore, C D, Wojcicki, S G, Hartnell, J, Irwin, G M, Newman, H B, Vahle, P, Zwaska, R, Bogert, D, Boehnlein, D J, Kordosky, M, Miller, W H, Grzelak, K, Bock, G J, Phan-Budd, S, Paley, J, Chapman, J D, Jensen, D, Ratchford, J, Qiu, X, Medeiros, M M, Jaffe, D E, Viren, B, Diwan, M V, Sharma, R, Schneps, J, Ling, J, Barr, G, Pawloski, G, Mualem, L, MINOS Collaboration, Oliver, W P, Radovic, A, Gouffon, P, Mayer, N, de Jong, J K, Kopp, S, Escobar, C O, Loiacono, L, Habig, A, Cronin-Hennessy, D, Mathis, M, Litchfield, P J, White, C, Mitchell, J, Holin, A, Mufson, S, Gallagher, H R, Gomes, R A, Mishra, S R, Zhang, K, Kasahara, S M S, Danko, I Z, Orchanian, M, Tzanakos, G, Musser, J, Nowak, J A, Nichol, R J, Hatcher, R, Lang, K, Nelson, J K, Weber, A, Sousa, A, Mehdiyev, R, Strait, M, Hylen, J, Pahlka, R B, Sanchez, M C, Urheim, J, Messier, M D, Isvan, Z, Rubin, H A, Goodman, M C, Frohne, M V, Marshak, M L, Speakman, B, James, C, Rosenfeld, C, Adamson, P, Naples, D, Kafka, T, Rebel, B, Koizumi, G, Schreckenberger, A, Cao, S V, Mann, W A, Coelho, J A B, Backhouse, C, Blake, A S T, Talaga, R L

2012

Overview

This paper reports measurements of atmospheric neutrino and antineutrino interactions in the MINOS Far Detector, based on 2553 live-days (37.9 kton-years) of data. A total of 2072 candidate events are observed. These are separated into 905 contained-vertex muons and 466 neutrino-induced rock-muons, both produced by charged-current \\(\\nu_{\\mu}\\) and \\(\\bar{\\nu}_{\\mu}\\) interactions, and 701 contained-vertex showers, composed mainly of charged-current \\(\\nu_{e}\\) and \\(\\bar{\\nu}_{e}\\) interactions and neutral-current interactions. The curvature of muon tracks in the magnetic field of the MINOS Far Detector is used to select separate samples of \\(\\nu_{\\mu}\\) and \\(\\bar{\\nu}_{\\mu}\\) events. The observed ratio of \\(\\bar{\\nu}_{\\mu}\\) to \\(\\nu_{\\mu}\\) events is compared with the Monte Carlo simulation, giving a double ratio of \\(R^{data}_{\\bar{\\nu}/\\nu}/R^{MC}_{\\bar{\\nu}/\\nu} = 1.03 \\pm 0.08 (stat.) \\pm 0.08 (syst.)\\). The \\(\\nu_{\\mu}\\) and \\(\\bar{\\nu}_{\\mu}\\) data are separated into bins of \\(L/E\\) resolution, based on the reconstructed energy and direction of each event, and a maximum likelihood fit to the observed \\(L/E\\) distributions is used to determine the atmospheric neutrino oscillation parameters. This fit returns 90% confidence limits of \\(|\\Delta m^{2}| = (1.9 \\pm 0.4) \\times 10^{-3} eV^{2}\\) and \\(sin^{2} 2\\theta > 0.86\\). The fit is extended to incorporate separate \\(\\nu_{\\mu}\\) and \\(\\bar{\\nu}_{\\mu}\\) oscillation parameters, returning 90% confidence limits of \\(|\\Delta m^{2}|-|\\Delta \\bar{m}^{2}| = 0.6^{+2.4}_{-0.8} \\times 10^{-3} eV^{2}\\) on the difference between the squared-mass splittings for neutrinos and antineutrinos.

• Publisher: Cornell University Library, arXiv.org
• Subject: Antineutrinos / Computer simulation / Confidence limits / Curvature / Monte Carlo simulation / Muons / Neutrinos / Parameters / Sensors