  We calculate the electroweak and finite width corrections to the decay of an
unpolarized top quark into a bottom quark and a $ W $-gauge boson where the
helicities of the $ W $ are specified as longitudinal, transverse-plus and
transverse-minus. Together with the $ O(\alpha_s) $ corrections these
corrections may become relevant for the determination of the mass of the top
quark through angular decay measurements.
