Search for anomalous couplings in the Wtb vertex from the measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector



Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Aben, R, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abreu, R
et al (show 2856 more authors) (2016) Search for anomalous couplings in the Wtb vertex from the measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector JOURNAL OF HIGH ENERGY PHYSICS, 2016 (4). 023-. ISSN 1029-8479, 1029-8479

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Abstract

Abstract: The electroweak production and subsequent decay of single top quarks is determined by the properties of the Wtb vertex. This vertex can be described by the complex parameters of an effective Lagrangian. An analysis of angular distributions of the decay products of single top quarks produced in the t -channel constrains these parameters simultaneously. The analysis described in this paper uses 4.6 fb−1 of proton-proton collision data at (Formula presented.) TeV collected with the ATLAS detector at the LHC. Two parameters are measured simultaneously in this analysis. The fraction f<inf>1</inf> of decays containing transversely polarised W bosons is measured to be 0.37 ± 0.07 (stat.⊕syst.). The phase δ<inf>−</inf> between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be −0.014π ± 0.036π (stat.⊕syst.). The correlation in the measurement of these parameters is 0.15. These values result in two-dimensional limits at the 95% confidence level on the ratio of the complex coupling parameters g<inf>R</inf> and V<inf>L</inf>, yielding Re[g<inf>R</inf>/V<inf>L</inf>] ∈ [−0.36, 0.10] and Im[g<inf>R</inf>/V<inf>L</inf>] ∈ [−0.17, 0.23] with a correlation of 0.11. The results are in good agreement with the predictions of the Standard Model.[Figure not available: see fulltext.]

Item Type: Article
Additional Information: 26 pages plus author list + cover pages (42 pages total), 8 figures, 2 tables, submitted to JHEP, All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2013-12
Uncontrolled Keywords: Hadron-Hadron scattering
Depositing User: Symplectic Admin
Date Deposited: 14 Mar 2017 11:44
Last Modified: 24 Jun 2026 19:51
DOI: 10.1007/JHEP04(2016)023
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3006016
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