Measurement of heavy quark forward-backward asymmetries and the B mixing parameter using Z decays recorded with the OPAL detector at LEP

This thesis deals with the measuremen t of the b and c quark forw ard-bac kward asymmetries of hadronic Z deca ys recorded with the OP AL exp erimen t at the electron positron collider LEP . After an overview over the di eren t kinds of hea vy avour forw ard-bac kward asymmetry measuremen ts made within the OP AL col- lab oration, one of the metho ds is describ ed in full detail. This metho d is based on the semileptonic b and c quark deca ys in order to identify primary b b and c c events. Tw o neural net works are used to separate the b b and c c events from eac h other and from the bac kground. The rst neural net work is trained to identify b->l-, the second to iden tify c ! ` + deca ys. A maxim um likeliho od t is used to extract the b and c quark forw ard-bac kward asymmetries A b FB and A c FB at three cen tre-of-mass energies p s and the average B mixing parameter from a sample with at least one iden ti ed electron or muon in the nal state. (not complete)