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Abdallah, J.; Adye, T.; Anjos, N.; Beccherle, R.; Bednyakov, V.A.; Behr, K.; Bertoli, G.; Black, K.M.; Blumenschein, U.; Bocci, A.; Buehrer, F.; Bulekov, O.; Calvet, D.; Caron, S.; Carter, J.R.; Cavaliere, V.; Chen, S.; Citterio, M.; Cox, B.E.; Davey, W.; De Sanctis, U.; Emeliyanov, D.; Falciano, S.; Farrell, S.; Farrington, S.M.; Ferrari, R.; Fletcher, G.T.; Franconi, L.; Gemmell, A.; Gostkin, M.I.; Grabowska-Bold, I.; Grohs, J.P.; Hallewell, G.D.; Hamal, P.; Hamity, G.N.; Harrington, R.D.; Hasegawa, Y.; Hayward, H.S.; Hirschbuehl, D.; Hod, N.; Ishitsuka, M.; Jenni, P.; Jones, G.; Kourkoumelis, C.; Kunigo, T.; Loch, P.; Lopes, L.; Mahboubi, K.; Martin-Haugh, S.; Meric, N.; Negri, G.; Nikolopoulos, K.; Nisius, R.; Okumura, Y.; Orr, R.S.; Padilla Aranda, C.; Pagáčová, M.; Palka, M.; Pasqualucci, E.; Piacquadio, G.; Pitt, M.; Poettgen, R.; Potamianos, K.; Price, D.; Primavera, M.; Prokofiev, K.; Prokoshin, F.; Przysiezniak, H.; Relich, M.; Rescigno, M.; Rinaldi, L.; Rubbo, F.; Sanchez Martinez, V.; Sarrazin, B.; Sbarra, C.; Schaetzel, S.; Schäfer, U.; Scheirich, D.; Schmieden, K.; Severini, H.; Shapiro, M.; Sjursen, T.B.; Snyder, S.; Soh, D.A.; Stavina, P.; Takubo, Y.; Tannoury, N.; Temming, K.K.; Terada, S.; Theveneaux-Pelzer, T.; Vanadia, M.; Vandelli, W.; Vu Anh, T.; Wang, J.; Wingerter-Seez, I.; Yang, H.; Yu, J.; Zambito, S.; Zeitnitz, C.; Zimmermann, R.
Physics letters. B, 01/2015, Letnik: 740, Številka: CJournal Article
This Letter presents a search at the LHC for s-channel single top-quark production in proton–proton collisions at a centre-of-mass energy of 8 TeV. The analyzed data set was recorded by the ATLAS detector and corresponds to an integrated luminosity of 20.3 fb−1. Selected events contain one charged lepton, large missing transverse momentum and exactly two b-tagged jets. A multivariate event classifier based on boosted decision trees is developed to discriminate s-channel single top-quark events from the main background contributions. The signal extraction is based on a binned maximum-likelihood fit of the output classifier distribution. The analysis leads to an upper limit on the s-channel single top-quark production cross-section of 14.6 pb at the 95% confidence level. The fit gives a cross-section of σs=5.0±4.3 pb, consistent with the Standard Model expectation.
