Top-Antitop Cross-Section Measurement Strategy with the ATLAS Detector at the LHC

A measurement of the top-antitop pair production cross-section in the dimuon channel with the ATLAS detector was made, using in a data sample of L = 32.1 pb−1 from the LHC’s 2010 pp collisions at sqrt(s) = 7 TeV. This analysis utilizes a binned likelihood fitting algorithm to separate signal and background events. This method increases the acceptance of the signal and thus may reduce the statistical uncertainty of the measurement. The cross-section is measured to be sigma_ttbar = 148.8 ± 39.8 (Stat.) ± (Syst.) pb using the missing transverse energy as the discriminating variable in the fit, in agreement with the results of the ATLAS Top Physics Working Group.