Calibrating b-tagging using ttbar Events

This note describes various studies of $b$-jet reconstruction and $b$-tagging in simulated ATLAS ttbar events. The performance of several jet algorithms on ttbar event $b$-jets is studied. Techniques for measuring the $b$-tagging efficiency directly from data ttbar events, using both tag counting and explicit $b$-jet selection, are described and compared. Finally, the optimisation of $b$-tagging for ttbar events, using both Monte Carlo and data samples, is discussed. Both semileptonic and dilepton ttbar decay channels are considered, for an initial integrated luminosity of 100 pb-1.