Corrections to quark asymmetries at LEP

The most precise measurement of the weak mixing angle sin 2θeffl at LEP is from the forward-backward asymmetry e+e-→bb at the Z-pole. In this note the QED and electroweak radiative corrections to obtain the pole asymmetry from the measured asymmetry for b- and c-quarks have been calculated using ZFITTER, which has been amended to allow a consistent treatment of partial two-loop corrections for the b-quark final asymmetries. A total correction of δAFBb=0.0019±0.0002 and δAFBc=0.0064±0.0001 has been found, where the remaining theoretical uncertainty is much too small to explain the apparent discrepancy between sin 2θeffl obtained from AFBb and from the left-right asymmetry at SLD. (orig.)