Top Quark Pair Production Cross-section Measurements in ATLAS in the Single Lepton+Jets Channel without b-tagging

This note summarises measurements of the ttbar cross-section in the lepton+jets channel using approximately 35 pb−1of ATLAS data collected in 2010. The data sample do not use b-tagging, and thus suffers different background and systematics that analyses with b-tagging. The measurements employ various techniques that are based on a binned maximum likelihood template fit and cut&count techniques on a data sample b-tagging. The measured ttbar cross sections are in good agreement with theory predictions.