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Measurement of the W boson polarisation in tt¯ events from pp collisions at √s = 8 TeV in the lepton + jets channel with ATLAS

dc.contributor.authorATLAS Collaboration
dc.date.accessioned2018-11-05T21:01:12Z
dc.date.available2018-11-05T21:01:12Z
dc.date.issued2017-04-26
dc.identifier.citationAaboud, M., Aad, G., Abbott, B. et al. Eur. Phys. J. C (2017) 77: 264. https://doi.org/10.1140/epjc/s10052-017-4819-4en_US
dc.identifier.urihttp://hdl.handle.net/1808/27209
dc.description.abstractThis 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.en_US
dc.description.sponsorshipSCOAP3en_US
dc.publisherSpringerOpenen_US
dc.rights© CERN for the benefit of the ATLAS collaboration 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.en_US
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/en_US
dc.titleMeasurement of the W boson polarisation in tt¯ events from pp collisions at √s = 8 TeV in the lepton + jets channel with ATLASen_US
dc.typeArticleen_US
kusw.kudepartmentPhysics and Astronomyen_US
dc.identifier.doi10.1140/epjc/s10052-017-4819-4en_US
kusw.oaversionScholarly/refereed, publisher versionen_US
kusw.oapolicyThis item meets KU Open Access policy criteria.en_US
dc.rights.accessrightsopenAccessen_US


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© CERN for the benefit of the ATLAS collaboration 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Except where otherwise noted, this item's license is described as: © CERN for the benefit of the ATLAS collaboration 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.