b-Jet Tagging Efficiency Calibration using the System8 Method

This Note describes a calibration of lifetime tagging efficiencies for b-quark jets involving semileptonic decays using the System8 method, designed to minimise the dependence on the quality of the description of the data by simulations by using three independent criteria applied to a data sample containing a muon associated with a jet to create eight comparisons between observed and expected event counts. The method uses the 2010 ATLAS dataset, amounting to an integrated luminosity of approximately 35 /pb collected at a centre-of-mass energy of 7 TeV. The results obtained using this method are compared to those obtained using an alternative method, relying on similar properties of semileptonic decays but making different assumptions.