Utilize este identificador para referenciar este registo:
https://hdl.handle.net/1822/39887
Título: | Observation of top-quark pair production in association with a photon and measurement of the t t ¯ γ production cross section in pp collisions at s =7 TeV using the ATLAS detector |
Autor(es): | Onofre, A. Castro, Nuno Filipe Silva Fernandes ATLAS Collaboration |
Palavras-chave: | Top physics Experimental results |
Data: | 2015 |
Editora: | American Physical Society |
Revista: | Physical Review D - Particles, Fields, Gravitation and Cosmology |
Citação: | Aad, G., Abbott, B., Abdallah, J., Abdel Khalek, S., Abdinov, O., Aben, R., . . . Zwalinski, L. (2015). Observation of top-quark pair production in association with a photon and measurement of the t t ¯ γ production cross section in pp collisions at s =7 TeV using the ATLAS detector. Physical Review D - Particles, Fields, Gravitation and Cosmology, 91(7). doi: 10.1103/PhysRevD.91.072007 |
Resumo(s): | A search is performed for top-quark pairs (tt¯) produced together with a photon (γ) with transverse momentum >20 GeV using a sample of tt¯ candidate events in final states with jets, missing transverse momentum, and one isolated electron or muon. The dataset used corresponds to an integrated luminosity of 4.59 fb−1 of proton--proton collisions at a center-of-mass energy of 7 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. In total 140 and 222 tt¯γ candidate events are observed in the electron and muon channels, to be compared to the expectation of 79±26 and 120±39 non-tt¯γ background events respectively. The production of tt¯γ events is observed with a significance of 5.3 standard deviations away from the null hypothesis. The tt¯γ production cross section times the branching ratio (BR) of the single-lepton decay channel is measured in a fiducial kinematic region within the ATLAS acceptance. The measured value is σfidtt¯γ=63±8(stat.)+17−13(syst.)±1(lumi.) fb per lepton flavor, in good agreement with the leading-order theoretical calculation normalized to the next-to-leading-order theoretical prediction of 48±10 fb. |
Tipo: | Artigo |
URI: | https://hdl.handle.net/1822/39887 |
DOI: | 10.1103/PhysRevD.91.072007 |
ISSN: | 1550-7998 1550-2368 |
Arbitragem científica: | yes |
Acesso: | Acesso aberto |
Aparece nas coleções: | LIP - Artigos/papers |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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ATLAS-20150203.pdf | 644,73 kB | Adobe PDF | Ver/Abrir |