Study of measurement of the $t\bar{t}$\ cross section in the electron + jets channel at ATLAS using kinematic information

The observation of the top quark will be an important milestone at LHC. We present a study of the prospects for measuring the $t\bar{t}$production cross-section with the ATLAS detector at a center-of-mass energy of 10~TeV with one electron, missing transverse energy, and at least four jets in the final state. The $t\bar{t}$\ signal is discriminated from background processes using kinematic information. Several kinematic variables are combined into a multivariate discriminant to maximize the separation between signal and background. The aim of this method is to make an early measurement of the $t\bar{t}$\ cross section. Once ATLAS has accumulated 50~pb$^{-1}$\ of integrated luminosity, then we expect to measure the $t\bar{t}$cross section to an accuracy of 7\% from statistical uncertainties and 26\% from systematic uncertainties.