Soft Electron Tagging

The presence of an electron coming from the semi-leptonic decay of a $B$ hadron can be used to tag $b$-jets. This note describes a soft electron tagging algorithm and its performance when applied to ATLAS Monte Carlo simulation data. Jets are built from the energy reconstructed in the electromagnetic and hadronic calorimeters with a cone algorithm. Electrons, reconstructed by a track-seeded algorithm, are sought among charged tracks associated to the jets. The tagging of jets originating from $b$ quarks is based on kinematics and on the identification capabilities of the inner tracker and the electromagnetic calorimeter. The performance of the electron identification and $b$-tagging procedure are presented. A $b$-jet tagging efficiency of about 7\% (including the inclusive $b\rightarrow e\nu X$ branching ratio of $\sim$ 20\%) is achieved for a light jet rejection of better than 100.