Measurement of the cross section of single leptonic ttbar events

Measuring the cross section of the ttbar->bWbW->bqqblv (lepton=muon) process at the LHC provides an essential test of the Standard Model. Predicted radiative corrections in the Standard Model and in models beyond the Standard Model can be constrained via this measurement. Also the mass of the top quark is a crucial parameter in these models. The Large Hadron Collider will collect an enormous amount of pp->ttbar events, which will in the semi-leptonic decay mode allow to measure the top quark mass via the measurement of the cross section of the process. An event selection is applied on the simulated data providing an event sample with a high signal-to-noise ratio. A cross section estimator is constructed which is therefore robust for deviations in the predicted cross section of the background processes. It is shown that the potential relative uncertainty on the cross section of the pp->ttbar->bWbW->bqqblv (l=muon) process is 0.6 (stat) +- 10.5 (syst) % for an integrated luminosity of 5fb-1.