Scalar mass dependence of angular variables in $t\bar tφ$ production

• Autor(a) principal: Azevedo, Duarte
• Data de Publicação: 2020
• Outros Autores: Capucha, Rodrigo, Onofre, A., Santos, Rui
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/1822/69371
• topic: Beyond Standard Model; CP violation; Ciências Naturais::Ciências Físicas; Science & Technology

In this paper we explore CP discrimination in the associated production of top-quark pairs ($t\bar{t}$) with a generic scalar boson ($\phi$) at the LHC. We probe the CP-sensitivity of several observables for a varying scalar boson mass and CP-number, either CP-even ($\phi=H$) or CP-odd ($\phi=A$), using dileptonic final states of the $t\bar{t}\phi$ system, with $\phi\rightarrow b\bar{b}$. We show that CP-searches are virtually impossible for $\phi$ boson masses above a few hundred GeV in this channel. A full phenomenological analysis was performed, using Standard Model background and signal events generated with MadGraph5 MC@NLO and reconstructed using a kinematic fit. The most sensitive CP-observables are used to compute Confidence Levels (CLs), as a function of luminosity, for the exclusion of different signal hypotheses with scalar and pseudoscalar boson masses that range from $m_\phi$ = 40 GeV up to 200 GeV. We finalize by analysing the impact of a measurement (or limit) of the CP-violating angle in the parameter space of a complex two-Higgs doublet model known as the C2HDM.