Evidence for the charge asymmetry in pptt̅ production at √s = 13 TeV with the ATLAS detector

Open Access
Authors
Publication date 08-2023
Journal Journal of High Energy Physics
Article number 077
Volume | Issue number 2023 | 8
Number of pages 89
Organisations
  • Faculty of Science (FNWI) - Institute of Physics (IoP)
  • Faculty of Science (FNWI) - Institute of Physics (IoP) - Institute for High Energy Physics (IHEF)
Abstract
nclusive and differential measurements of the top–antitop (tt̅)  charge asymmetry Att̅C and the leptonic asymmetry Aιι-C are presented in proton–proton collisions at √ = 13 TeV recorded by the ATLAS experiment at the CERN Large Hadron Collider. The measurement uses the complete Run 2 dataset, corresponding to an integrated luminosity of 139 fb−1, combines data in the single-lepton and dilepton channels, and employs reconstruction techniques adapted to both the resolved and boosted topologies. A Bayesian unfolding procedure is performed to correct for detector resolution and acceptance effects. The combined inclusive tt̅ charge asymmetry is measured to be Att̅C= 0.0068 ± 0.0015, which differs from zero by 4.7 standard deviations. Differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the tt̅ system. Both the inclusive and differential measurements are found to be compatible with the Standard Model predictions, at next-to-next-to-leading order in quantum chromodynamics perturbation theory with next-to-leading-order electroweak corrections. The measurements are interpreted in the framework of the Standard Model effective field theory, placing competitive bounds on several Wilson coefficients.

Document type Article
Language English
Published at https://doi.org/10.1007/JHEP08(2023)077
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