First results on top-quarks from ATLAS

The search for first top-quark pair candidate events and the related background studies using data-driven techniques are reported for about 300 inverse nb of 7 TeV proton-proton collision data delivered by the Large Hadron Collider (LHC) and collected with the ATLAS detector. Selected events are characterized by the presence of high-pT isolated charged lepton(s), high jet multiplicity, jet(s) identified as originating from b-quark by a secondary vertex tagger algorithm, and missing transverse energy. They reveal kinematics properties consistent with top pair production.