Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at √s=8 TeV



Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H
et al (show 5193 more authors) (2020) Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at √s=8 TeV JOURNAL OF HIGH ENERGY PHYSICS, 2020 (8). 051-. ISSN 1126-6708, 1029-8479

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Abstract

The combination of measurements of the W boson polarization in top quark decays performed by the ATLAS and CMS collaborations is presented. The measurements are based on proton-proton collision data produced at the LHC at a centre-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of about 20 fb−1 for each experiment. The measurements used events containing one lepton and having different jet multiplicities in the final state. The results are quoted as fractions of W bosons with longitudinal (F<inf>0</inf>), left-handed (F<inf>L</inf>), or right-handed (F<inf>R</inf>) polarizations. The resulting combined measurements of the polarization fractions are F<inf>0</inf> = 0.693 ± 0.014 and F<inf>L</inf> = 0.315 ± 0.011. The fraction F<inf>R</inf> is calculated from the unitarity constraint to be F<inf>R</inf> = −0.008 ± 0.007. These results are in agreement with the standard model predictions at next-to-next-to-leading order in perturbative quantum chromodynamics and represent an improvement in precision of 25 (29)% for F<inf>0</inf> (F<inf>L</inf>) with respect to the most precise single measurement. A limit on anomalous right-handed vector (V<inf>R</inf>), and left- and right-handed tensor (g<inf>L</inf>, g<inf>R</inf>) tWb couplings is set while fixing all others to their standard model values. The allowed regions are [−0.11, 0.16] for V<inf>R</inf>, [−0.08, 0.05] for g<inf>L</inf>, and [−0.04, 0.02] for g<inf>R</inf>, at 95% confidence level. Limits on the corresponding Wilson coefficients are also derived. [Figure not available: see fulltext.]

Item Type: Article
Additional Information: Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/TOP-19-004 (CMS Public Pages) and https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2018-02 (ATLAS Public Pages)
Uncontrolled Keywords: Hadron-Hadron scattering (experiments), Top physics
Depositing User: Symplectic Admin
Date Deposited: 21 Sep 2020 07:48
Last Modified: 23 May 2026 02:45
DOI: 10.1007/JHEP08(2020)051
Open Access URL: https://link.springer.com/article/10.1007%2FJHEP08...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3101957
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