Measurements of the charge asymmetry in top-quark pair production in the dilepton final state at $\sqrt{s}=8$ TeV with the ATLAS detector

Abstract

Measurements of the top--antitop quark pair production charge asymmetry in the dilepton channel, characterized by two high-$p_{\mathrm{T}}$ leptons (electrons or muons), are presented using data corresponding to an integrated luminosity of $20.3$ ${\text{fb}}^{-1}$ from $pp$ collisions at a center-of-mass energy of $\sqrt{s}=8$ TeV collected with the ATLAS detector at the Large Hadron Collider at CERN. Inclusive and differential measurements as a function of the invariant mass, transverse momentum, and longitudinal boost of the $t\bar{t}$ system are performed both in the full phase space and in a fiducial phase space closely matching the detector acceptance. Two observables are studied: $A_{\text{C}}^{\ell \ell }$ based on the selected leptons and $A_{\text{C}}^{t\bar{t}}$ based on the reconstructed $t\bar{t}$ final state. The inclusive asymmetries are measured in the full phase space to be $A_{\text{C}}^{\ell \ell }=0.008\pm 0.006$ and $A_{\text{C}}^{t\bar{t}}=0.021\pm 0.016$, which are in agreement with the Standard Model predictions of $A_{\text{C}}^{\ell \ell }=0.0064\pm 0.0003$ and $A_{\text{C}}^{t\bar{t}}=0.0111\pm 0.0004$.

29 pages plus author list + cover pages (45 pages total), 8 figures, 4 tables, published in Physical Review D, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2015-08/

References in corpus (23)

• PYTHIA 6.4 Physics and Manual
• Parton distributions for the LHC
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• New parton distributions for collider physics
• Two-loop soft anomalous dimensions for single top quark associated production with a W- or H-
• The Catchment Area of Jets
• The PDF4LHC Working Group Interim Recommendations
• Jet energy measurement and its systematic uncertainty in proton-proton collisions at $\sqrt{s}=7$ TeV with the ATLAS detector
• Electron and photon energy calibration with the ATLAS detector using LHC Run 1 data
• Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton-proton collision data
• Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton-proton collision data
• First measurement of the forward-backward charge asymmetry in top quark pair production
• The Bulk RS KK-gluon at the LHC
• Top Quarks, Axigluons and Charge Asymmetries at Hadron Colliders
• t tbar W and t tbar Z Hadroproduction at NLO accuracy in QCD with Parton Shower and Hadronization effects
• Measurement of the charge asymmetry in top quark pair production in pp collisions at sqrt(s) = 7 TeV using the ATLAS detector
• Inclusive and differential measurements of the t t-bar charge asymmetry in proton-proton collisions at sqrt(s) = 7 TeV
• Measurement of the forward-backward asymmetry in top quark-antiquark production in ppbar collisions using the lepton+jets channel
• Massive color-octet bosons and the charge asymmetries of top quarks at hadron colliders
• Differential top-antitop cross-section measurements as a function of observables constructed from final-state particles using pp collisions at $\sqrt{s}=7$ TeV in the ATLAS detector
• Asymmetries in top quark pair production at hadron colliders
• Measurement of the charge asymmetry in dileptonic decays of top quark pairs in $pp$ collisions at $\sqrt{s}=7$ TeV using the ATLAS detector
• Portrait of a colour octet

Cited by in corpus (5)

• Top-Quark Physics: Status and Prospects
• Top-quark physics at the Large Hadron Collider
• Observing the Top Energy Asymmetry at the LHC
• Staying on Top of SMEFT-Likelihood Analyses
• Charge asymmetry measurements in $t\bar{t}$ events at the LHC