Flavour Tagging at LHCb

To do precise CP violation measurements, the most possible accurate knowledge of the flavour at production of the reconstructed B meson is required. This poster summarizes the flavour tagging performances for the LHCb experiment. We use same side an opposite side algorithms to establish wheter the meson contained a b or a b\bar quark. The final decision is obtained through a combination of several methods. The use of control channels, decays to a flavour specific final state, will allow to determine the wrong tag fraction \omega (the probability of a tag to be wrong), which can be used as input for the determination of CKM unitary triangle angles.