ttbar differential cross section measurement at sqrt(s)=7 TeV with CMS detector

The Compact Muon Solenoid (CMS) is one of the two large multipurpose experiments at the Large Hadron Collider (LHC). With the very large integrated luminosity recorded in 2011, the amount of data allows for a first differential analysis of top quark pair cross sections. Normalized differential top quark pair production cross sections in pp-collisions at 7 TeV are measured using the decay channels into two opposite-sign leptons (muons or electrons). The cross section distributions are measured as a function of kinematic observables of the final state leptons and the top quarks, as reconstructed by algorithms fitting the event topologies. The presentation places particular focus on the determination of the systematic errors of the measurement.