UBC Faculty Research and Publications

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


Differential and double-differential distributions of kinematic variables of leptons from decays of top-quark pairs (tt¯) 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 √ s = 13 TeV and correspond to an integrated luminosity of 140 fb−1 . The measurements use events containing an oppositely charged eµ 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 tt¯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 σtt¯ = 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.

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