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https://hdl.handle.net/1822/48900
Título: | Measurement of the W boson polarisation in tt¯ events from pp collisions at s√ = 8 TeV in the lepton + jets channel with ATLAS |
Autor(es): | Onofre, A. Castro, Nuno Filipe Silva Fernandes ATLAS Collaboration |
Data: | 2017 |
Editora: | Springer Verlag |
Revista: | European Physical Journal C: Particles and Fields |
Citação: | 13. Aaboud, M., Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Abeloos, B., . . . Zwalinski, L. (2017). Measurement of the W boson polarisation in tt¯ events from pp collisions at √s = 8 TeV in the lepton + jets channel with ATLAS. [Article]. European Physical Journal C, 77(4). doi: 10.1140/epjc/s10052-017-4819-4 |
Resumo(s): | This paper presents a measurement of the polarisation of W bosons from tt¯ decays, reconstructed in events with one high-p T lepton and at least four jets. Data from pp collisions at the LHC were collected at s√ = 8 TeV and correspond to an integrated luminosity of 20.2 fb−1. The angle θ∗ between the b-quark from the top quark decay and a direct W boson decay product in the W boson rest frame is sensitive to the W boson polarisation. Two different W decay products are used as polarisation analysers: the charged lepton and the down-type quark for the leptonically and hadronically decaying W boson, respectively. The most precise measurement of the W boson polarisation via the distribution of cosθ∗ is obtained using the leptonic analyser and events in which at least two of the jets are tagged as b-quark jets. The fitted fractions of longitudinal, left- and right-handed polarisation states are F0= 0.709 ± 0.019, FL= 0.299 ± 0.015 and FR= −0.008 ± 0.014, and are the most precisely measured W boson polarisation fractions to date. Limits on anomalous couplings of the Wtb vertex are set. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/48900 |
DOI: | 10.1140/epjc/s10052-017-4819-4 |
ISSN: | 1434-6044 |
e-ISSN: | 1434-6052 |
Versão da editora: | https://link.springer.com/article/10.1140%2Fepjc%2Fs10052-017-4819-4 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | LIP - Artigos/papers |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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10.1140_epjc_s10052-017-4819-4.pdf | 2,57 MB | Adobe PDF | Ver/Abrir |