Measurement of the charge asymmetry in top-quark pair production in association with a photon with the ATLAS experiment

Abstract

A measurement of the charge asymmetry in top-quark pair ($t\bar{t}$) production in association with a photon is presented. The measurement is performed in the single-lepton $t\bar{t}$ decay channel using proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider at CERN at a centre-of-mass-energy of 13 TeV during the years 2015-2018, corresponding to an integrated luminosity of 139 fb${}^{-1}$. The charge asymmetry is obtained from the distribution of the difference of the absolute rapidities of the top quark and antiquark using a profile likelihood unfolding approach. It is measured to be $A_{\text{C}}=-0.003\pm 0.029$ in agreement with the Standard Model expectation.

39 pages in total, 4 figures, 2 tables. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2021-29

References in corpus (17)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• An Introduction to PYTHIA 8.2
• Herwig++ Physics and Manual
• Two-loop soft anomalous dimensions for single top quark associated production with a W- or H-
• Automatic spin-entangled decays of heavy resonances in Monte Carlo simulations
• Next-to-next-to-leading-order collinear and soft gluon corrections for t-channel single top quark production
• NNLL resummation for s-channel single top quark production
• Performance of electron and photon triggers in ATLAS during LHC Run 2
• Muon reconstruction and identification efficiency in ATLAS using the full Run 2 $pp$ collision data set at $\sqrt{s}=13$ TeV
• Performance of the ATLAS muon triggers in Run 2
• Top quark asymmetry from a non-Abelian horizontal symmetry
• Inclusive and differential measurements of the t t-bar charge asymmetry in proton-proton collisions at sqrt(s) = 7 TeV
• Asymmetries in top quark pair production at hadron colliders
• The top quark forward-backward asymmetry at approximate N${}^3$LO
• Using Final State Pseudorapidities to Improve s-channel Resonance Observables at the LHC
• The top quark charge asymmetry in $t\bar{t}\gamma$ production at the LHC
• Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark Pair Production

Cited by in corpus (5)

• Reconstruction of Unstable Heavy Particles Using Deep Symmetry-Preserving Attention Networks
• Search for heavy right-handed Majorana neutrinos in the decay of top quarks produced in proton$-$proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
• Measurement of the top-quark production cross-section and charge asymmetry at LHCb
• One-loop amplitudes for $t\bar{t}j$ and $t\bar{t}\gamma$ productions at the LHC through $\mathcal{O}({\epsilon }^2)$
• Photon production in top quark events at ATLAS and CMS