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Search for the standard model Higgs boson produced in association with top quarks and decaying into a b¯b pair in pp collisions at √s=13  TeV with the ATLAS detector

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Resumo:A search for the standard model Higgs boson produced in association with a top-quark pair, t¯tH, is presented. The analysis uses 36.1  fb−1 of pp collision data at √s=13  TeV collected with the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The search targets the H→b¯b decay mode. The selected events contain either one or two electrons or muons from the top-quark decays, and are then categorized according to the number of jets and how likely these are to contain b-hadrons. Multivariate techniques are used to discriminate between signal and background events, the latter being dominated by t¯t+jets production. For a Higgs boson mass of 125 GeV, the ratio of the measured t¯tH signal cross-section to the standard model expectation is found to be μ=0.84+0.64−0.61. A value of μ greater than 2.0 is excluded at 95% confidence level (C.L.) while the expected upper limit is μ<1.2 in the absence of a t¯tH signal.
Autores principais:Onofre, A.
Outros Autores:Castro, Nuno Filipe; ATLAS Collaboration
Ano:2018
País:Portugal
Tipo de documento:artigo
Tipo de acesso:acesso aberto
Instituição associada:Universidade do Minho
Idioma:inglês
Origem:RepositóriUM - Universidade do Minho
Descrição
Resumo:A search for the standard model Higgs boson produced in association with a top-quark pair, t¯tH, is presented. The analysis uses 36.1  fb−1 of pp collision data at √s=13  TeV collected with the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The search targets the H→b¯b decay mode. The selected events contain either one or two electrons or muons from the top-quark decays, and are then categorized according to the number of jets and how likely these are to contain b-hadrons. Multivariate techniques are used to discriminate between signal and background events, the latter being dominated by t¯t+jets production. For a Higgs boson mass of 125 GeV, the ratio of the measured t¯tH signal cross-section to the standard model expectation is found to be μ=0.84+0.64−0.61. A value of μ greater than 2.0 is excluded at 95% confidence level (C.L.) while the expected upper limit is μ<1.2 in the absence of a t¯tH signal.