Top quark cross section measurement in ATLAS: Commissioning Analysis

An accurate determination of the top‐quark pair production cross‐section at the LHC provides a valuable check of the Standard Model. In this article we present a commissioning analysis to measure to quark cross section with the ATLAS detector. The cross section is determined in the semileptonic channel using a counting method, based solely on counting the numbers of top candidate events that pass selection, and subtracting all backgrounds in order to get the yield of tt̄ events in the sample. Our cross section study is performed without relying on the tagging of b‐quark initiated jets.