Measurement of top quark pair production with the ATLAS detector

A measurement of the production cross-section for top quark pairs in pp collisions at $\sqrt{s}=7$ TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. The inclusive top quark pair production cross-section is measured to be $\sigma = 145 \pm 31 ^{+42}_{-27}$ pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations