The Top Quark Pair Production Cross Section Measurement at LHC-ATLAS

Measurements of the production cross section of top-quark pairs () in proton-proton (pp) collisions at TeV are presented using 0.70 fb⁻¹ of data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in the dilepton topologies characterized by two oppositelysigned leptons, multi-jets, and large missing transverse energy. The result is (stat.) (syst.) ±8(lumi.) pb. Further application of b-quark flavor tagging technique (b-tag) in the selection can discard backgrounds that do not contain b-quarks in their final states. The result with the b-tag is (stat.) (syst.) (lumi.) pb. Both of the two results agree with the Standard Model prediction and with each other.