Evidence for the charge asymmetry in pp -> tt(bar) production at CMS = 13 TeV with the ATLAS detector
Abstract
Inclusive and differential measurements of the top-antitop (t-t) charge asymmetry
At-t
C and the leptonic asymmetry A'-'
C are presented in proton-proton collisions at p s = 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 t-t charge asymmetry is measured to be At-t
C = 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 t-t 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.