The ATLAS detector started collecting data in 2022 at the centre-of-mass energy √s = 13.6 TeV. In this report, an analysis of proton-proton collision
data collected in August 2022 by the ATLAS detector at the LHC is shown. The analysis aim is to measure the top-quark pair production cross-section and its ratio to the Z boson production cross-section. Some of the first plots showing a comparison between Run 3 data and predictions in the eμ final state are presented.
