Evidence for the associated production of the Higgs boson and a top quark pair with the ATLAS detector

A search for the associated production of the Higgs boson with a top quark pair (ttH¯ ) is reported. The search is performed in multilepton final states using a dataset corresponding to an integrated luminosity of 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at a center...

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Detalles Bibliográficos
Autores: Aaboud, M., Aad, G., Abbott, B., Abdinov, O., Abeloos, B., Alconada Verzini, María Josefina, Alonso, Francisco, Arduh, Francisco Anuar, Dova, Maria Teresa, Hoya, Joaquín, Monticelli, Fernando Gabriel, Wahlberg, Hernan Pablo, Bossio Sola, Jonathan David, Daneri, María Florencia, Devesa, Maria Roberta, Marceca, Gino, Otero y Garzon, Gustavo Javier, Piegaia, Ricardo Nestor, Sacerdoti, Sabrina, Zinonos, Z., Zinser, M., Ziolkowski, M., Živković, L., Zobernig, G., Zoccoli, A., Zoch, K., Nedden, M. zur, Zorbas, T. G., Zou, R., Zwalinski, L., The ATLAS Collaboration
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2018
País:Argentina
Institución:Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio:CONICET Digital (CONICET)
Idioma:inglés
OAI Identifier:oai:ri.conicet.gov.ar:11336/115324
Acceso en línea:http://hdl.handle.net/11336/115324
Access Level:acceso abierto
Palabra clave:ATLAS
HIGGS
High Energy Physics
https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
Descripción
Sumario:A search for the associated production of the Higgs boson with a top quark pair (ttH¯ ) is reported. The search is performed in multilepton final states using a dataset corresponding to an integrated luminosity of 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at a center-of-mass energy √ s = 13 TeV at the Large Hadron Collider. Higgs boson decays to WW∗ , ττ, and Z Z∗ are targeted. Seven final states, categorized by the number and flavor of charged-lepton candidates, are examined for the presence of the Standard Model Higgs boson with a mass of 125 GeV and a pair of top quarks. An excess of events over the expected background from Standard Model processes is found with an observed significance of 4.1 standard deviations, compared to an expectation of 2.8 standard deviations. The best fit for the ttH¯ production cross section is σ(ttH¯ ) = 790+230 −210 fb, in agreement with the Standard Model prediction of 507+35 −50 fb. The combination of this result with other ttH¯ searches from the ATLAS experiment using the Higgs boson decay modes to bb¯, γγ and Z Z∗ → 4`, has an observed significance of 4.2 standard deviations, compared to an expectation of 3.8 standard deviations. This provides evidence for the ttH¯ production mode.

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