Search for the Standard Model Higgs boson produced in association with top quarks and decaying into $b\bar{b}$ in pp collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector

G. Aad 1 S. Albrand 2 J. Brown 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 D. Boumediene 4 Emmanuel Busato 4 D. Calvet 4 S. Calvet 4 J. Donini 4 E. Dubreuil 4 N. Ghodbane 4 G. Gilles 4 Ph. Gris 4 H. Liao 4 R. Madar 4 D. Pallin 4 S.M. Romano Saez 4 C. Santoni 4 D. Simon 4 Timothée Theveneaux-Pelzer 4 F. Vazeille 4 L. Alio 1 M. Barbero 1 Y. Coadou 1 S. Diglio 1 F. Djama 1 L. Feligioni 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 5 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 O. Duccu 1, 6 Z. Barnovska 7 N. Berger 7 M. Delmastro 7 L. Di Ciaccio 7 T.K.O. Doan 7 S. Elles 7 T. Hryn’ova 7 S. Jézéquel 7 I. Koletsou 7 R. Lafaye 7 J. Leveque 7 N. Massol 7 G. Sauvage 7 E. Sauvan 7 O. Simard 7 T. Todorov 7 I. Wingerter-Seez 7 M.K. Ayoub 8 A. Bassalat 8 C. Becot 8 S. Binet 8 C. Bourdarios 8 J.B. de Vivie De Regie 8 D. Delgove 8 L. Duflot 8 M. Escalier 8 L. Fayard 8 D. Fournier 8 E.L. Gkougkousis 8 J.-F. Grivaz 8 T. Guillemin 8 F. Hariri 8 S. Henrot-Versillé 8 J. Hrivnac 8 L. Iconomidou-Fayard 8 M. Kado 8 A. Lounis 8 N. Makovec 8 N. Morange 8 C. Nellist 8 L. Poggioli 8 P. Puzo 8 A. Renaud 8 D. Rousseau 8 G. Rybkin 8 A.C. Schaffer 8 E. Scifo 8 L. Serin 8 S. Simion 8 R. Tanaka 8 H.L. Tran 8 D. Zerwas 8 Zhen Zhang 8 Y. Zhao 8
Abstract : A search for the Standard Model Higgs boson produced in association with a pair of top quarks, $t\bar{t}H$, is presented. The analysis uses 20.3 fb$^{-1}$ of pp collision data at $\sqrt{s}$ = 8 TeV, collected with the ATLAS detector at the Large Hadron Collider during 2012. The search is designed for the H to $b\bar{b}$ decay mode and uses events containing one or two electrons or muons. In order to improve the sensitivity of the search, events are categorised according to their jet and b-tagged jet multiplicities. A neural network is used to discriminate between signal and background events, the latter being dominated by $t\bar{t}$+jets production. In the single-lepton channel, variables calculated using a matrix element method are included as inputs to the neural network to improve discrimination of the irreducible $t\bar{t}$+$b\bar{b}$ background. No significant excess of events above the background expectation is found and an observed (expected) limit of 3.4 (2.2) times the Standard Model cross section is obtained at 95% confidence level. The ratio of the measured $t\bar{t}H$ signal cross section to the Standard Model expectation is found to be $\mu$ = 1.5 $\pm$ 1.1 assuming a Higgs boson mass of 125 GeV.
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Article dans une revue
European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2015, 75, pp.349. 〈10.1140/epjc/s10052-015-3543-1〉
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Soumis le : vendredi 20 mars 2015 - 08:37:51
Dernière modification le : mercredi 16 mai 2018 - 15:10:07

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G. Aad, S. Albrand, J. Brown, J. Collot, S. Crépé-Renaudin, et al.. Search for the Standard Model Higgs boson produced in association with top quarks and decaying into $b\bar{b}$ in pp collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector. European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2015, 75, pp.349. 〈10.1140/epjc/s10052-015-3543-1〉. 〈in2p3-01133670〉

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