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

G. Aad 1 S. Albrand 2 J. Collot 2 S. Crépé-Renaudin 2 P.A. Delsart 2 C. Gabaldon 2 M.H. Genest 2 J.Y. Hostachy 2 F. Ledroit-Guillon 2 A. Lleres 2 A. Lucotte 2 F. Malek 2 C. Monini 2 J. Stark 2 B. Trocmé 2 M. Wu 2 G. Rahal 3 M.K. Ayoub 4 A. Bassalat 4 C. Bécot 4 S. Binet 4 C. Bourdarios 4 D. Delgove 4 J-B. de Vivie De Regie 4 L. Duflot 4 M. Escalier 4 L. Fayard 4 D. Fournier E.L. Gkougkousis 4 J-F. Grivaz 4 T. Guillemin 4 F. Hariri 4 S. Henrot-Versille 4 J. Hrivnac 4 L. Iconomidou-Fayard 4 M. Kado 4 A. Lounis 4 N. Makovec 4 N. Morange 4 C. Nellist P. Petroff 4 L. Poggioli 4 P. Puzo 4 A. Renaud 4 D. Rousseau 4 G. Rybkin 4 A.C. Schaffer 4 E. Scifo 4 L. Serin 4 S. Simion 4 R. Tanaka 4 D. Zerwas 4 Zhongkai Zhang 4 Y. Zhao 4 Z. Barnovska 5 N. Berger 5 M. Delmastro 5 L. Di Ciaccio 5 S. Elles 5 C. Goy 5 T. Hryn’ova 5 S. Jézéquel 5 I. Koletsou 5 R. Lafaye 5 J. Levêque 5 N. Massol 5 P. Mastrandea 5 G. Sauvage 5 E. Sauvan 5 O. Simard 5 T. Todorov 5 I. Wingerter-Seez 5 E. Yatsenko 5 D. Boumediene 6 E. Busato 6 D. Calvet 6 S. Calvet 6 J. Donini 6 E. Dubreuil 6 G. Gilles 6 Ph. Gris 6 H. Liao 6 R. Madar 6 D. Pallin 6 S.M. Romano Saez 6 C. Santoni 6 D. Simon 6 T. Theveneaux-Pelzer 6 F. Vazeille 6 L. Alio 1 M. Barbero 1 Y. Coadou 1 C. Diaconu 1 S. Diglio 1 F. Djama 1 O. Duccu 1 L. Feligioni 1 J. Gao 1 G.D. Hallewell 1 F. Hubaut 1 S.J. Kahn 1 E. B. F. G. Knoops 1 E. Le Guirriec 1 J. Liu 1 K. Liu 1 D. Madaffari 1 K. Mochizuki 1 E. Monnier 1 S. Muanza 1 Y. Nagai 1 E. Nagy 1 P. Pralavorio 1 A. Rozanov 1 T. Serre M. Talby 1 R.E. Ticse Torres 1 E. Tiouchichine 1 S. Tisserant 1 J. Toth 1 F. Touchard 1 L. Vacavant 1
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.
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Physics Letters B, Elsevier, 2016, 756, pp.228-246. 〈10.1016/j.physletb.2016.03.017〉
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Dernière modification le : mardi 24 juillet 2018 - 15:46:14

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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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