Experimental study of charm at LEP by the D* meson channel with ALEPH detector

This research deals with the analysis of some 500 000 neutral Z bosons recorded with the ALEPH detector between 1989 and 1991. The physical subject concerns the study of charm at LEP and more precisely the production of charmed mesons, charged and excited: D*. Charged mesons are reconstructed in the channel with two pions and one kaon in the final state via the decay of neutral charmed one. We have measured simultaneously the ratio of D* meson production, the relative contribution of charm and beauty in D* meson production and the average fraction of the beam energy carried away by the D* meson at the time of its fragmentation. The charge asymmetry of charm has been also measured thanks to the high purity in charm events obtained by the D* tagging and finally allows us to infer the value of the electroweak mixing angle