Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at √s = 8 TeV
Aad, Georges; Abbott, Brad; Abbott, Dale C.; Abed Abud, Adam; Abeling, Kira; Abhayasinghe, Deshan Kavishka; Abidi, Syed Haider; AbouZeid, Ossama Sherif Alexander; Abraham, Nadine L.; Abramowicz, Halina; Bjørke, Kristian; Bugge, Magnar Kopangen; Cameron, David Gordon; Catmore, James Richard; Garonne, Vincent; Heggelund, Andreas Løkken; Hellesund, Simen; Morisbak, Vanja; Oppen, Henrik; Ould-Saada, Farid; Pedersen, Maiken; Read, Alexander Lincoln; Rye, Eli Bæverfjord; Røhne, Ole Myren; Sandaker, Heidi; Vadla, Knut Oddvar Høie; Buanes, Trygve; Djuvsland, Julia Isabell; Eigen, Gerald; Fomin, Nikolai; Lee, Graham Richard; Lipniacka, Anna; Martin dit Latour, Bertrand; Stugu, Bjarne; Træet, Are Sivertsen; Abreu, Henso; Abulaiti, Yiming; Acharya, Bobby S.; Achkar, Baida; Adam, Lennart; Adam-Bourdarios, Claire; Adamczyk, Leszek; Adamek, Lukas; Adelman, Jareed; Adersberger, Michael; Adigüzel, Aytül; Adorni, Sofia; Adye, Tim; Affolder, Anthony Allen; Afik, Yoav; ATLAS, Collaboration
Journal article, Peer reviewed
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Original versionJournal of High Energy Physics (JHEP). 2020, 051. 10.1007/JHEP08(2020)051
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 (F0), left-handed (FL), or right-handed (FR) polarizations. The resulting combined measurements of the polarization fractions are F0 = 0.693 ± 0.014 and FL = 0.315 ± 0.011. The fraction FR is calculated from the unitarity constraint to be FR = −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 F0 (FL) with respect to the most precise single measurement. A limit on anomalous right-handed vector (VR), and left- and right-handed tensor (gL, gR) tWb couplings is set while fixing all others to their standard model values. The allowed regions are [−0.11, 0.16] for VR, [−0.08, 0.05] for gL, and [−0.04, 0.02] for gR, at 95% confidence level. Limits on the corresponding Wilson coefficients are also derived.