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https://hdl.handle.net/1822/39947
Título: | Search for flavour-changing neutral current top quark decays t → Hq in pp collisions at √s=8 TeV with the ATLAS detector |
Autor(es): | Onofre, A. Castro, Nuno Filipe Silva Fernandes ATLAS Collaboration |
Palavras-chave: | Hadron-Hadron Scattering Top Physics Higgs Physics FCNC Interactions |
Data: | 2015 |
Editora: | Springer Verlag |
Revista: | Journal of High Energy Physics |
Citação: | Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Aben, R., . . . Zwalinski, L. (2015). Search for flavour-changing neutral current top quark decays t → Hq in pp collisions at √s=8 TeV with the ATLAS detector. Journal of High Energy Physics, 2015(12), 1-65. doi: 10.1007/jhep12(2015)061 |
Resumo(s): | A search for flavour-changing neutral current decays of a top quark to an uptype quark (q = u, c) and the Standard Model Higgs boson, where the Higgs boson decays to bb¯¯, is presented. The analysis searches for top quark pair events in which one top quark decays to Wb, with the W boson decaying leptonically, and the other top quark decays to Hq. The search is based on pp collisions at s√=8 TeV recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider and uses an integrated luminosity of 20.3 fb−1. Data are analysed in the lepton-plus-jets final state, characterised by an isolated electron or muon and at least four jets. The search exploits the high multiplicity of b-quark jets characteristic of signal events, and employs a likelihood discriminant that uses the kinematic differences between the signal and the background, which is dominated by tt¯→WbWb decays. No significant excess of events above the background expectation is found, and observed (expected) 95% CL upper limits of 0.56% (0.42%) and 0.61% (0.64%) are derived for the t → Hc and t → Hu branching ratios respectively. The combination of this search with other ATLAS searches in the H → γγ and H → WW *, ττ decay modes significantly improves the sensitivity, yielding observed (expected) 95% CL upper limits on the t → Hc and t → Hu branching ratios of 0.46% (0.25%) and 0.45% (0.29%) respectively. The corresponding combined observed (expected) upper limits on the |λ tcH | and |λ tuH | couplings are 0.13 (0.10) and 0.13 (0.10) respectively. These are the most restrictive direct bounds on tqH interactions measured so far. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/39947 |
DOI: | 10.1007/jhep12(2015)061 |
ISSN: | 1029-8479 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | LIP - Artigos/papers |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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art-3A10.1007-2FJHEP12-282015-29061.pdf | 1,35 MB | Adobe PDF | Ver/Abrir |