Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector

G. Aad 1 Z. Barnovska 2 N. Berger 2 M. Delmastro 2 L. Di Ciaccio 2 S. Elles 2 T. Hryn’ova 2 S. Jézéquel 2 I. Koletsou 2 R. Lafaye 2 J. Leveque 2 N. Massol 2 G. Sauvage 2 E. Sauvan 2 O. Simard 2 T. Todorov 2 I. Wingerter-Seez 2 E. Yatsenko 2 G . Rahal 3 M.K. Ayoub 4 A. Bassalat 4 C. Becot 4 S. Binet 4 C. Bourdarios 4 J.B. de Vivie De Regie 4 D. Delgove 4 L. Duflot 4 M. Escalier 4 L. Fayard 4 D. Fournier 4 E.L. Gkougkousis 4 J.-F. Grivaz 4 T. Guillemin 4 F. Hariri 4 S. Henrot-Versillé 4 J. Hrivnac 4 L. Iconomidou-Fayard 4 M. Kado 4 A. Lounis 4 N. Makovec 4 N. Morange 4 C. Nellist 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 H.L. Tran 4 D. Zerwas 4 Zhongkai Zhang 4 Y. Zhao 4 D. Boumediene 5 Emmanuel Busato 5 D. Calvet 5 S. Calvet 5 J. Donini 5 E. Dubreuil 5 G. Gilles 5 Ph. Gris 5 H. Liao 5 R. Madar 5 D. Pallin 5 S.M. Romano Saez 5 C. Santoni 5 D. Simon 5 Timothée Theveneaux-Pelzer 5 F. Vazeille 5 L. Alio 1 M. Barbero 1 Y. Coadou 1 C. Diaconu 1 S. Diglio 1 F. Djama 1 O. Duccu 1, 6 L. Feligioni 1 J. Gao 7 G.D. Hallewell 1 F. Hubaut 1 S.J. Kahn 1 E. B. F. G. Knoops 1 E. Le Guirriec 1 J. Liu 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 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 8 J. Brown 8 J. Collot 8 S. Crépé-Renaudin 8 P.A. Delsart 8 C. Gabaldon 8 M.H. Genest 8 J.Y. Hostachy 8 F. Ledroit-Guillon 8 A. Lleres 8 A. Lucotte 8 F. Malek 8 C. Monini 8 J. Stark 8 B. Trocmé 8 M. Wu 8
Abstract : A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb$^{-1}$ of proton-proton collision data recorded by the ATLAS experiment at $\sqrt{s}=8$ TeV at the Large Hadron Collider. Five final states, targeting the decays $H\to WW^*$, $\tau\tau$, and $ZZ^*$, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons ($e$ or $\mu$) without a hadronically decaying $\tau$ lepton; three light leptons; two same-charge light leptons with a hadronically decaying $\tau$ lepton; four light leptons; and one light lepton and two hadronically decaying $\tau$ leptons. No significant excess of events is observed above the background expectation. The best fit for the $t\bar t H$ production cross section, assuming a Higgs boson mass of 125 GeV, is $2.1 ^{+1.4}_{-1.2}$ times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. The $p$-value for compatibility with the background-only hypothesis is $1.8\sigma$; the expectation in the presence of a Standard Model signal is $0.9\sigma$.
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Physics Letters B, Elsevier, 2015, 749, pp.519-541. 〈10.1016/j.physletb.2015.07.079〉
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Soumis le : lundi 22 juin 2015 - 15:39:26
Dernière modification le : mercredi 16 mai 2018 - 15:10:06

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G. Aad, Z. Barnovska, N. Berger, M. Delmastro, L. Di Ciaccio, et al.. Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector. Physics Letters B, Elsevier, 2015, 749, pp.519-541. 〈10.1016/j.physletb.2015.07.079〉. 〈in2p3-01166348〉

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