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https://hdl.handle.net/1822/63610
Título: | The Role of the $t{\bar t}h$ Rest Frame in Direct Top-Quark Yukawa Coupling Measurements |
Autor(es): | Ferroglia, Andrea Fiolhais, Miguel C. N. Gouveia, Emanuel Onofre, A. |
Data: | 2019 |
Editora: | American Physical Society |
Revista: | Physical Review D |
Citação: | Ferroglia, A., Fiolhais, M. C. N., Gouveia, E., & Onofre, A. (2019). Role of the t t h rest frame in direct top-quark Yukawa coupling measurements ROLE of the t t h REST FRAME in ⋯ FERROGLIA, FIOLHAIS, GOUVEIA, and ONOFRE. [Article]. Physical Review D, 100(7). doi: 10.1103/PhysRevD.100.075034 |
Resumo(s): | This paper studies new possibilities to directly measure a hypothetical $CP$-odd (pseudoscalar) component in the top-quark Yukawa coupling. In particular, the role of the $t{\bar t} h$ center-of-mass rest frame in the associated production of a top pair and a $h$ boson at the LHC is explored. The $h$ boson is assumed to have both a $CP$-even (scalar) and a $CP$-odd coupling to the top quark. The relative strength of the scalar and pseudoscalar components is regulated by an angle $\alpha$. Observables sensitive to the nature of the top-quark Yukawa coupling are proposed. These observables are defined in terms of the transverse and longitudinal projections of $t$, $\bar{t}$ and $h$ momenta with respect to the beam axis in the $t{\bar t} h$ rest frame. Distributions differential with respect to those observables are evaluated up to NLO in QCD. These distributions are found to be sensitive to the $CP$ nature of the coupling. Dileptonic final states of the $t{\bar t} h$ system (with $h\rightarrow b\bar b$) are used, after fast DELPHES detector simulation and full event reconstruction through a kinematic fit, as a case study to test the observables' sensitivity to the $CP$ nature of the coupling. Confidence levels are presented as a function of the total integrated LHC luminosity for the case of exclusion of a pure $CP$-odd coupling against the Standard Model $CP$-even hypothesis. By using observables evaluated in the $t{\bar t} h$ system, the luminosity needed to directly probe the $CP$ properties of the top-quark Yukawa coupling at the High-Luminosity run of the LHC can be decreased by a few hundred inverse femtobarns, when compared to analyses that use observables in the laboratory rest frame. In addition, transverse momentum distributions of the $h$ boson and top quarks are found to provide no more discriminant power than a counting experiment. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/63610 |
DOI: | 10.1103/PhysRevD.100.075034 |
ISSN: | 2470-0010 |
e-ISSN: | 2470-0029 |
Versão da editora: | https://journals.aps.org/prd/abstract/10.1103/PhysRevD.100.075034 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | LIP - Artigos/papers |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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PhysRevD.100.075034.pdf | 1,91 MB | Adobe PDF | Ver/Abrir |