Determination of Top Quark Pair Production Cross-Section

An accurate determination of the top quark pair production cross-section at the LHC provides a valuable check of the Standard Model. Given the high statistics which will be available, corresponding to about one top-quark pair per second, at a luminosity of 10^33 cm^−2s^−1, the cross-section measurement can be performed relatively fast after the turn-on of the LHC. Prospects for measuring the total top quark pair production cross-section with the ATLAS detector during the initial period of LHC are presented in this note. The cross-section is determined in the semi-leptonic channel, and in the dilepton channel. For the semi-leptonic channel we perform the measurement both with and without relying on the tagging of b-quark initiated jets.