Measurement of the top quark pair production cross section in pp collisions at root s=7 TeV in dilepton final states with ATLAS

Abstract

A measurement of the production cross section of top quark pairs (View the MathML sourcett¯) in proton–proton collisions at a center-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider is reported. Candidate events are selected in the dilepton topology with large missing transverse energy and at least two jets. Using a data sample corresponding to an integrated luminosity of 35 pb−135 pb−1, a View the MathML sourcett¯ production cross section View the MathML sourceσtt¯=177±20(stat.)±14(syst.)±7(lum.) pb is measured for an assumed top quark mass of mt=172.5 GeVmt=172.5 GeV. A second measurement requiring at least one jet identified as coming from a b quark yields a comparable result, demonstrating that the dilepton final states are consistent with being accompanied by b-quark jets. These measurements are in good agreement with Standard Model predictions.