Optimization and calibration of the LHCb flavour tagging performance using 2010 data

We report on the optimization and calibration of the flavour tagging algorithms using the decays $B^0 \to D^{*-}\mu^+ \nu_{\mu}$, $B^+ \to J/\psi K^+$ and $B^0 \to J/\psi K^{*0}$ and $\sim$ 35 pb$^{-1}$ of data from the LHCb 2010 physics run. After a data-driven optimization and calibration, we measured an effective tagging efficiency for the opposite-side tagger combination of 1.97 $\pm$ 0.18% in the $B^0 \to D^{*-}\mu^+ \nu_{\mu}$ channel, 1.97 $\pm$ 0.31% in the $B^+ \to J/\psi K^+$ channel and 2.52 $\pm$ 0.82% in the $B^0 \to J/\psi K^{*0}$ channel. For the combination of same-side pion and opposite-side taggers the corresponding values are: 2.87 $\pm$ 0.32%, 2.38 $\pm$ 0.33% and 2.82$\pm$ 0.87%.