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

Franconi, Laura; Haug, Sigve; Weber, Michele; Anders, John Kenneth; Fehr, Armin; Beck, Hans Peter; Ereditato, Antonio; Lehmann, Niklaus; Miucci, Antonio; Weston, Thomas Daniel (2020). Combination of the W boson polarization measurements in top quark decays using ATLAS and CMS data at \sqrts = 8 TeV. Journal of High Energy Physics, 2020(8) Springer 10.1007/JHEP08(2020)051

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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.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)
08 Faculty of Science > Physics Institute
10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)

UniBE Contributor:

Franconi, Laura, Haug, Sigve, Weber, Michele, Anders, John Kenneth, Ilg, Armin, Beck, Hans Peter, Ereditato, Antonio, Lehmann, Niklaus, Miucci, Antonio, Weston, Thomas Daniel

Subjects:

500 Science > 530 Physics

ISSN:

1029-8479

Publisher:

Springer

Language:

English

Submitter:

BORIS Import LHEP

Date Deposited:

21 Apr 2021 09:05

Last Modified:

02 Mar 2023 23:34

Publisher DOI:

10.1007/JHEP08(2020)051

Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwaehnt

BORIS DOI:

10.48350/155564

URI:

https://boris.unibe.ch/id/eprint/155564

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