Polarized top decay into polarized W t(up arrow)-> W(up arrow)+b at O(alpha(s))

We consider the decay of a polarized top quark into a polarized W-boson plu s a bottom quark, followed by the decay of the W-boson into a pair of lepto ns or quarks. The: polar angle distribution of the top spin relative to the : W-momentum and the polar angle distribution of the lepton (or quark) in t he W-rest frame is governed by three polarized and three unpolarized tate f unctions which are related to the double density matrix elements of the dec ay t --> W+ + b. We obtain analytical expressions for the O(alpha(5)) radia tive corrections to the three polarized and three unpolarized rate function s. We also provide a comprehensive discussion of the dependence of the long itudinal, transverse and normal polarization of the top quarks produced at e(+)e(-)-colliders on beam polarization parameters. (C) 1999 Published by E lsevier Science B.V. All rights reserved.