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

Barton, Adam Edward and Beattie, Michael and Borissov, Guennadi and Bouhova-Thacker, Evelina Vassileva and Dearnaley, William and Fox, Harald and Grimm, Kathryn Ann Tschann and Henderson, Robert Charles William and Hughes, Gareth and Jones, Roger William Lewis and Kartvelishvili, Vakhtang and Long, Robin Eamonn and Love, Peter Allan and Maddocks, Harvey and Skinner, Malcolm and Smizanska, Maria and Walder, James William and Wharton, Andy (2016) Search for anomalous couplings in the W tb 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 (4). ISSN 1029-8479

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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 √s =7 TeV collected with the ATLAS detector at the LHC. Two parameters are measured simultaneously in this analysis. The fraction f 1 of decays containing transversely polarised W bosons is measured to be 0.37 ± 0.07 (stat.⊕syst.). The phase δ − 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 R and V L, yielding Re[g R /V L] ∈ [−0.36, 0.10] and Im[g R /V L] ∈ [−0.17, 0.23] with a correlation of 0.11. The results are in good agreement with the predictions of the Standard Model.

Item Type: Journal Article
Journal or Publication Title: Journal of High Energy Physics
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/3100/3106
Subjects:
Departments: Faculty of Science and Technology > Physics
ID Code: 79367
Deposited By: ep_importer_pure
Deposited On: 06 May 2016 11:48
Refereed?: Yes
Published?: Published
Last Modified: 21 Oct 2019 00:41
URI: https://eprints.lancs.ac.uk/id/eprint/79367

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