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

TL;DR

This paper reports measurements of the charge asymmetry in top-quark pair production in the dilepton final state at 8 TeV using ATLAS data, finding results consistent with Standard Model predictions.

Contribution

It presents the first detailed measurements of charge asymmetry in top-quark pairs in dilepton channels at 8 TeV with both inclusive and differential analyses.

Findings

No significant deviation from Standard Model expectations

Measured asymmetries are consistent with theoretical predictions

Performed both full and fiducial phase space analyses

Abstract

Measurements of the top--antitop quark pair production charge asymmetry in the dilepton channel, characterized by two high-${p}_{\rm{T}}$ leptons (electrons or muons), are presented using data corresponding to an integrated luminosity of 20.3 $\textrm{fb}^{-1}$ from $pp$ collisions at a center-of-mass energy $\sqrt{s} = 8$~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: $A_C^{\ell \ell}$ based on the selected leptons and $A_C^{t\bar{t}}$ based on the reconstructed $t\bar{t}$ final state. No significant deviation from the Standard Model expectations is observed.