Measurement of the forward backward asymmetry of c andb quarks at the Z pole using reconstructed D mesons

A measurement of the forward–backward asymmetry of and on the Z resonance is performed using about 3.5 million hadronic Z decays collected by the DELPHI detector at LEP in the years 1992 to 1995. The heavy quark is tagged by the exclusive reconstruction of several D meson decay modes. The forward–backward asymmetries for c andb quarks at the Z resonance are determined to be: The combination of these results leads to an effective electroweak mixing angle of: Received: 9 February 1999 / Revised version: 26 April 1999 / Published online: 3 August 1999