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 s=8 TeV at the Large Hadron Collider. Five final states, targeting the decays H→WW*, ττ, and ZZ*, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one light lepton and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt-H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1-1.2+1.4 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 1.8σ the expectation in the presence of a Standard Model signal is 0.9σ. \copyright 2015 CERN for the benefit of the ATLAS Collaboration.
Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector / Aad, G; Aloisio, Alberto; Alviggi, Mariagrazia; Canale, Vincenzo; DELLA PIETRA, Massimo; DELLA VOLPE, Domenico; Merola, Leonardo; Conventi, Francesco; Perrella, Sabrina; Rossi, Elvira; SANCHEZ PINEDA, ARTURO RODOLFO; Carlino, Gianpaolo; DE ASMUNDIS, Riccardo; DI DONATO, Camilla; Doria, Alessandra; Iengo, Paolo; Izzo, Vincenzo; Sekhniaidze, Givi; Et, A. l.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 749:(2015), pp. 519-541. [10.1016/j.physletb.2015.07.079]
Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector
ALOISIO, ALBERTO;ALVIGGI, MARIAGRAZIA;CANALE, VINCENZO;DELLA PIETRA, MASSIMO;DELLA VOLPE, DOMENICO;MEROLA, LEONARDO;CONVENTI, FRANCESCO;PERRELLA, SABRINA;ROSSI, ELVIRA;SANCHEZ PINEDA, ARTURO RODOLFO;CARLINO, GIANPAOLO;DE ASMUNDIS, Riccardo;DI DONATO, CAMILLA;IENGO, PAOLO;IZZO, VINCENZO;
2015
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 s=8 TeV at the Large Hadron Collider. Five final states, targeting the decays H→WW*, ττ, and ZZ*, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one light lepton and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt-H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1-1.2+1.4 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 1.8σ the expectation in the presence of a Standard Model signal is 0.9σ. \copyright 2015 CERN for the benefit of the ATLAS Collaboration.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.