Inclusive and differential cross-sections for dilepton tt overline production measured in root s = 13 TeV pp collisions with the ATLAS detector

Differential and double-differential distributions of kinematic variables of leptons from decays of top-quark pairs (tbar t) are measured using the full LHC Run 2 data sample collected with the ATLAS detector. The data were collected at a pp collision energy of root s = 13 TeV and correspond to an integrated luminosity of 140 fb-1. The measurements use events containing an oppositely charged e-mu pair and b-tagged jets. The results are compared with predictions from several Monte Carlo generators. While no prediction is found to be consistent with all distributions, a better agreement with measurements of the lepton pT distributions is obtained by reweighting the tbar t sample so as to reproduce the topquark pT distribution from an NNLO calculation. The inclusive top-quark pair production cross-section is measured as well, both in a fiducial region and in the full phase-space. The total inclusive cross-section is found to be sigma(tbar t) = 829 +- 1 (stat) +- 13 (syst) +- 8 (lumi) +- 2 (beam) pb where the uncertainties are due to statistics, systematic effects, the integrated luminosity and the beam energy. This is in excellent agreement with the theoretical expectation.