Search for dark matter produced in association with a single top quark in √ s = 13 TeV pp collisions with the ATLAS detector

• Autor(a) principal: Fiolhais, M. C. N.
• Data de Publicação: 2021
• Outros Autores: Gonçalo, R., Veloso, F., Wolters, H., ATLAS Collaboration
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/103919; https://doi.org/10.1140/epjc/s10052-021-09566-y

This paper presents a search for dark matter in the context of a two-Higgs-doublet model together with an additional pseudoscalar mediator, a, which decays into the dark-matter particles. Processes where the pseudoscalar mediator is produced in association with a single top quark in the 2HDM+a model are explored for the first time at the LHC. Several final states which include either one or two charged leptons (electrons or muons) and a significant amount of missing transversemomentum are considered. The analysis is based on proton–proton collision data collected with the ATLAS experiment at √ s = 13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 fb−1. No significant excess above the Standard Model predictions is found. The results are expressed as 95% confidence-level limits on the parameters of the signal models considered.