CERN Accelerating science

ATLAS Note
Report number ATLAS-CONF-2019-026
Title Inclusive and differential measurement of the charge asymmetry in $t\bar{t}$ events at 13 TeV with the ATLAS detector
Corporate Author(s) The ATLAS collaboration
Collaboration ATLAS Collaboration
Publication 2019
Imprint 11 Jul 2019
Number of pages mult.
Note All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/CONFNOTES/ATLAS-CONF-2019-026
Subject category Particle Physics - Experiment
Accelerator/Facility, Experiment CERN LHC ; ATLAS
Free keywords 13 TeV ; 1 lepton ; Boosted ; Differential measurement ; EFT ; ttbar asymmetry measurements ; Top properties measurements
Abstract A measurement of the top-antitop ($t\bar t$) charge asymmetry $A_{\text{C}}$ is presented using data corresponding to an integrated luminosity of 139 fb$^{-1}$ of $\sqrt{s} = 13$ TeV of $pp$ collisions recorded by the ATLAS experiment at the Large Hadron Collider, CERN. The measurement is performed in the single-lepton channel ($e$ or $\mu$) combining both the resolved and boosted topologies of top quark decays. A Bayesian unfolding procedure is used to infer the asymmetry at parton level, correcting for detector resolution and acceptance effects. The inclusive $t\bar t$ charge asymmetry is measured as $A_{\text{C}} = 0.0060 \pm 0.0015 \textrm{(stat+syst.)}$, which differs from zero by 4 standard deviations. Differential measurements are performed as a function of the invariant mass and longitudinal boost of the $t\bar t$ system. Both inclusive and differential measurements are found to be compatible with the Standard Model predictions, at NNLO in perturbation theory with NLO electroweak corrections.
Related document superseded by: CERN-EP-2022-166

Corresponding record in: Inspire


 Record created 2019-07-11, last modified 2022-08-26