Further studies on simulation of top-quark production for the ATLAS experiment at √s = 13 TeV

This note summarizes recent studies of modern Monte Carlo generator setups for the pair production of top quarks at the LHC. Samples at a center of mass energy of 7 or 13 TeV have been generated using various setup such as MadGraph5_aMC@NLO+Pythia8 at leading order, MadGraph5_aMC@NLO+Pythia8 at next-to-leading order using the FxFx merging scheme prescription, Sherpa 2.2 and Powheg+Herwig7. The performance of these samples for several physical observables are compared to the ATLAS baseline generator configuration, Powheg+Pythia6, and to √s = 7 TeV ATLAS measurements. New studies of tt production in association with bb pair are also presented.