# Evidence for single top-quark production in the $s$-channel in proton-proton collisions at $\sqrt{s}=$8 TeV with the ATLAS detector using the Matrix Element Method

Abstract : This Letter presents evidence for single top-quark production in the $s$-channel using proton-proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS detector at the CERN Large Hadron Collider. The analysis is performed on events containing one isolated electron or muon, large missing transverse momentum and exactly two $b$-tagged jets in the final state. The analysed data set corresponds to an integrated luminosity of 20.3 fb$^{-1}$. The signal is extracted using a maximum-likelihood fit of a discriminant which is based on the matrix element method and optimized in order to separate single-top-quark $s$-channel events from the main background contributions, which are top-quark pair production and $W$ boson production in association with heavy-flavour jets. The measurement leads to an observed signal significance of 3.2 standard deviations and a measured cross-section of $\sigma_s=4.8\pm0.8$(stat.)$^{+1.6}_{-1.3}$(syst.) pb, which is consistent with the Standard Model expectation. The expected significance for the analysis is 3.9 standard deviations.
Type de document :
Article dans une revue
Physics Letters B, Elsevier, 2016, 756, pp.228-246. 〈10.1016/j.physletb.2016.03.017〉

http://hal.in2p3.fr/in2p3-01231360
Contributeur : Emmanuelle Vernay <>
Soumis le : vendredi 20 novembre 2015 - 08:42:36
Dernière modification le : mardi 22 mai 2018 - 21:48:10

### Citation

G. Aad, S. Albrand, J. Collot, S. Crépé-Renaudin, P.A. Delsart, et al.. Evidence for single top-quark production in the $s$-channel in proton-proton collisions at $\sqrt{s}=$8 TeV with the ATLAS detector using the Matrix Element Method. Physics Letters B, Elsevier, 2016, 756, pp.228-246. 〈10.1016/j.physletb.2016.03.017〉. 〈in2p3-01231360〉

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