Measurements of fiducial cross-sections for $t\bar{t}$ production with one or two additional $b$-jets in $pp$ collisions at $\sqrt{s}$ = 8 TeV using the ATLAS detector

G. Aad 1 Z. Barnovska 2 N. Berger 2 M. Delmastro 2 L. Di Ciaccio 2 T.K.O. Doan 2 S. Elles 2 C. Goy 2 T. Hryn’ova 2 S. Jézéquel 2 I. Koletsou 2 R. Lafaye 2 J. Leveque 2 N. Massol 2 P. Mastrandrea 2 G. Sauvage 2 E. Sauvan 2 O. Simard 2 T. Todorov 2 I. Wingerter-Seez 2 E. Yatsenko 2 G . Rahal 3 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 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 1 M. Talby 1 R.E. Ticse Torres 1 E. Tiouchichine 1 S. Tisserant 1 J. Toth 1 F. Touchard 1 L. Vacavant 1 S. Albrand 4 J. Collot 4 S. Crépé-Renaudin 4 P.A. Delsart 4 C. Gabaldon 4 M.H. Genest 4 J.Y. Hostachy 4 F. Ledroit-Guillon 4 A. Lleres 4 A. Lucotte 4 F. Malek 4 C. Monini 4 J. Stark 4 B. Trocmé 4 M. Wu 4 M.K. Ayoub 5 A. Bassalat 5 C. Bécot 5 S. Binet 5 C. Bourdarios 5 D. Delgove 5 J-B. de Vivie De Regie 5 L. Duflot 5 M. Escalier 5 L. Fayard 5 D. Fournier 5 E.L. Gkougkousis 5 J-F. Grivaz 5 T. Guillemin 5 F. Hariri 5 S. Henrot-Versille 5 J. Hrivnac 5 L. Iconomidou-Fayard 5 M. Kado 5 A. Lounis 5 N. Makovec 5 N. Morange 5 C. Nellist 5 P. Petroff 5 L. Poggioli 5 P. Puzo 5 A. Renaud 5 D. Rousseau 5 G. Rybkin 5 A.C. Schaffer 5 E. Scifo 5 L. Serin 5 S. Simion 5 R. Tanaka 5 D. Zerwas 5 Zhongkai Zhang 5 Y. Zhao 5 D. Boumediene 6 Emmanuel 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 Timothée Theveneaux-Pelzer 6 F. Vazeille 6
Abstract : Fiducial cross-sections for $t\bar{t}$ production with one or two additional $b$-jets are reported, using an integrated luminosity of 20.3 fb$^{-1}$ of proton--proton collisions at a centre-of-mass energy of 8 TeV at the Large Hadron Collider, collected with the ATLAS detector. The cross-section times branching ratio for $t\bar{t}$ events with at least one additional $b$-jet is measured to be 950 $\pm$ 70 (stat.) $^{+240}_{-190}$ (syst.) fb in the lepton-plus-jets channel and 50 $\pm$ 10 (stat.) $^{+15}_{-10}$ (syst.) fb in the $e \mu$ channel. The cross-section times branching ratio for events with at least two additional $b$-jets is measured to be 19.3 $\pm$ 3.5 (stat.) $\pm$ 5.7 (syst.) fb in the dilepton channel ($e \mu$,\,$\mu\mu$, and \,$ee$) using a method based on tight selection criteria, and 13.5 $\pm$ 3.3 (stat.) $\pm$ 3.6 (syst.) fb using a looser selection that allows the background normalisation to be extracted from data. The latter method also measures a value of 1.30 $\pm$ 0.33 (stat.) $\pm$ 0.28 (syst.)\% for the ratio of $t\bar{t}$ production with two additional $b$-jets to $t\bar{t}$ production with any two additional jets. All measurements are in good agreement with recent theory predictions.
Type de document :
Article dans une revue
European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2016, 76, pp.11. 〈10.1140/epjc/s10052-015-3852-4〉
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Soumis le : vendredi 28 août 2015 - 11:04:48
Dernière modification le : lundi 22 octobre 2018 - 09:42:01

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G. Aad, Z. Barnovska, N. Berger, M. Delmastro, L. Di Ciaccio, et al.. Measurements of fiducial cross-sections for $t\bar{t}$ production with one or two additional $b$-jets in $pp$ collisions at $\sqrt{s}$ = 8 TeV using the ATLAS detector. European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2016, 76, pp.11. 〈10.1140/epjc/s10052-015-3852-4〉. 〈in2p3-01187948〉

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