Publicação
A search for top-squark pair production, in final states containing a top quark, a charm quark and missing transverse momentum, using the 139 fb-1 of pp collision data collected by the ATLAS detector
| Resumo: | This paper presents a search for top-squark pair production in final states with a top quark, a charm quark and missing transverse momentum. The data were collected with the ATLAS detector during LHC Run 2 and correspond to an integrated luminosity of \( 139 \, \text{fb}^{-1} \) of proton-proton collisions at a centre-of-mass energy of \( \sqrt{s} = 13 \, \text{TeV} \). The analysis is motivated by an extended Minimal Supersymmetric Standard Model featuring a non-minimal flavour violation in the second- and third-generation squark sector. The top squark in this model has two possible decay modes, either \( \tilde{t}_1 \rightarrow c\tilde{\chi}^0_1 \) or \( \tilde{t}_1 \rightarrow t\tilde{\chi}^0_1 \), where the \( \tilde{\chi}^0_1 \) is undetected. The analysis is optimised assuming that both of the decay modes are equally probable, leading to the most likely final state of \( tc + E_{\text{miss}}^T \). Good agreement is found between the Standard Model expectation and the data in the search regions. Exclusion limits at 95% CL are obtained in the \( m(\tilde{t}_1) \) vs. \( m(\tilde{\chi}^0_1) \) plane and, in addition, limits on the branching ratio of the \( \tilde{t}_1 \rightarrow t\tilde{\chi}^0_1 \) decay as a function of \( m(\tilde{t}_1) \) are also produced. Top-squark masses of up to 800 GeV are excluded for scenarios with light neutralinos, and top-squark masses up to 600 GeV are excluded in scenarios where the neutralino and the top squark are almost mass degenerate. |
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| Autores principais: | Castro, Nuno Filipe |
| Outros Autores: | Onofre, A.; ATLAS Collaboration |
| Assunto: | Beyond Standard Model Hadron-Hadron Scattering Supersymmetry |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | This paper presents a search for top-squark pair production in final states with a top quark, a charm quark and missing transverse momentum. The data were collected with the ATLAS detector during LHC Run 2 and correspond to an integrated luminosity of \( 139 \, \text{fb}^{-1} \) of proton-proton collisions at a centre-of-mass energy of \( \sqrt{s} = 13 \, \text{TeV} \). The analysis is motivated by an extended Minimal Supersymmetric Standard Model featuring a non-minimal flavour violation in the second- and third-generation squark sector. The top squark in this model has two possible decay modes, either \( \tilde{t}_1 \rightarrow c\tilde{\chi}^0_1 \) or \( \tilde{t}_1 \rightarrow t\tilde{\chi}^0_1 \), where the \( \tilde{\chi}^0_1 \) is undetected. The analysis is optimised assuming that both of the decay modes are equally probable, leading to the most likely final state of \( tc + E_{\text{miss}}^T \). Good agreement is found between the Standard Model expectation and the data in the search regions. Exclusion limits at 95% CL are obtained in the \( m(\tilde{t}_1) \) vs. \( m(\tilde{\chi}^0_1) \) plane and, in addition, limits on the branching ratio of the \( \tilde{t}_1 \rightarrow t\tilde{\chi}^0_1 \) decay as a function of \( m(\tilde{t}_1) \) are also produced. Top-squark masses of up to 800 GeV are excluded for scenarios with light neutralinos, and top-squark masses up to 600 GeV are excluded in scenarios where the neutralino and the top squark are almost mass degenerate. |
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