Utilize este identificador para referenciar este registo:
https://hdl.handle.net/1822/87768
Título: | Measurement of the polarisation of single top quarks and antiquarks produced in the t-channel at root s=13 TeV and bounds on the tWb dipole operator from the ATLAS experiment |
Autor(es): | Castro, Nuno Filipe Onofre, A. ATLAS Collaboration |
Palavras-chave: | Hadron-Hadron Scattering Top Physics |
Data: | 2022 |
Editora: | Springer |
Revista: | Journal of High Energy Physics |
Citação: | Aad, G., Abbott, B., Abbott, D. C., Abud, A. A., Abeling, K., Abhayasinghe, D. K., . . . Collaboration, A. (2022). Measurement of the polarisation of single top quarks and antiquarks produced in the t-channel at root s=13 TeV and bounds on the tWb dipole operator from the ATLAS experiment. JOURNAL OF HIGH ENERGY PHYSICS(11). doi: 10.1007/jhep11(2022)040 |
Resumo(s): | A simultaneous measurement of the three components of the top-quark and top-antiquark polarisation vectors in t-channel single-top-quark production is presented. This analysis is based on data from proton–proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb−1, collected with the ATLAS detector at the LHC. Selected events contain exactly one isolated electron or muon, large missing transverse momentum and exactly two jets, one being b-tagged. Stringent selection requirements are applied to discriminate t-channel single-top-quark events from the background contributions. The top-quark and top-antiquark polarisation vectors are measured from the distributions of the direction cosines of the charged-lepton momentum in the top-quark rest frame. The three components of the polarisation vector for the selected top-quark event sample are Px′ = 0.01 ± 0.18, Py′ = −0.029 ± 0.027, Pz′ = 0.91 ± 0.10 and for the top-antiquark event sample they are Px′ = −0.02 ± 0.20, Py′ = −0.007 ± 0.051, Pz′ = 0.79 ± 0.16. Normalised differential cross-sections corrected to a fiducial region at the stable-particle level are presented as a function of the charged-lepton angles for top-quark and top-antiquark events inclusively and separately. These measurements are in agreement with Standard Model predictions. The angular differential cross-sections are used to derive bounds on the complex Wilson coefficient of the dimension-six OtW operator in the framework of an effective field theory. The obtained bounds are CtW ∈ [−0.9, 1.4] and CitW ∈ [−0.8, 0.2], both at 95% confidence level. [Figure not available: see fulltext.]. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/87768 |
DOI: | 10.1007/jhep11(2022)040 |
ISSN: | 1126-6708 |
e-ISSN: | 1029-8479 |
Versão da editora: | https://link.springer.com/article/10.1007/JHEP11(2022)040 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | LIP - Artigos/papers |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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JHEP11(2022)040.pdf | 2,5 MB | Adobe PDF | Ver/Abrir |
Este trabalho está licenciado sob uma Licença Creative Commons