Evidence for $\nu_\mu \to \nu_\tau$ appearance in the CNGS neutrino beam with the OPERA experiment

• Main Authors: Aleksandrov, A, Anokhina, A, Ariga, A, Ariga, T, Dhahbi, A. Ben, Bertolin, A, Buonaura, A, Buontempo, S, Buettner, B, Chaussard, L, Chiarella, V, Chukanov, A, Consiglio, L, De Serio, M, Sanchez, P. Del Amo, Di Ferdinando, D, Dmitrievski, S, Dracos, M, Dusini, S, Ebert, J, Ferber, T, Fini, R. A, Fukuda, T, Galati, G, Garfagnini, A, Goldberg, J, Gornushkin, Y, Grella, G, Grianti, F, Guler, M, Gustavino, C, Hagner, C, Hakamata, K, Hara, T, Hayakawa, T, Hierholzer, M, Hollnagel, A, Hosseini, B, Ishida, H, Ishiguro, K, Jollet, C, Kamiscioglu, C, Kawada, J, Kim, J. H, Kimura, M, Komatsu, M, Lauria, A, Ljubicic, A, Longhin, A, Marteau, J, Medinaceli, E, Meregaglia, A, Migliozzi, P, Mikado, S, Miyanishi, M, Miyashita, E, Monacelli, P, Montesi, M. C, Morishima, K, Muciaccia, M. T, Naka, T, Nakamura, M, Nakatsuka, Y, Olshevsky, A, Ozaki, K, Paoloni, A, Pastore, A, Patrizii, L, Pessard, H, Pistillo, C, Podgrudkov, D, Polukhina, N, Pozzato, M, Pretzl, K, Rescigno, R, Roda, M, Roganova, T, Rosa, G, Sato, O, Sato, Y, Schmidt-Parzefal, W, Shakiryanova, I, Sheshukov, A, Shibuya, H, Shoziyoev, G, Simone, S, Sirri, G, Spinetti, M, Starkov, N, Strauss, T, Tenti, M, Terranova, F, Vilain, P, Vladimirov, M, Yoon, C. S, Yoshida, J, Yoshimoto, M, Zaitsev, Y, Zemskova, S, Zghiche, A
• Format: Journal Article
• Language: English
• Published: 09-01-2014
• Subjects: Physics - High Energy Physics - Experiment; Physics - Instrumentation and Detectors
• DOI: 10.48550/arxiv.1401.2079

Phys. Rev. D 89, 051102 (2014) The OPERA experiment is designed to search for $\nu_{\mu} \rightarrow
\nu_{\tau}$ oscillations in appearance mode i.e. through the direct observation
of the $\tau$ lepton in $\nu_{\tau}$ charged current interactions. The
experiment has taken data for five years, since 2008, with the CERN Neutrino to
Gran Sasso beam. Previously, two $\nu_{\tau}$ candidates with a $\tau$ decaying
into hadrons were observed in a sub-sample of data of the 2008-2011 runs. Here
we report the observation of a third $\nu_\tau$ candidate in the
$\tau^-\to\mu^-$ decay channel coming from the analysis of a sub-sample of the
2012 run. Taking into account the estimated background, the absence of
$\nu_{\mu} \rightarrow \nu_{\tau}$ oscillations is excluded at the 3.4 $\sigma$
level.