SEMILEPTONIC 6 FERMION PROCESSES AT FUTURE E(-) COLLIDERS - SIGNAL AND IRREDUCIBLE BACKGROUND FOR TOP AND WWZ PHYSICS()E()

We compute several total and differential cross sections relevant to t op and WWZ physics at future e(+)e(-) colliders, taking into account t he full set of Feynman diagrams for six fermion final states. We also include in our calculations initial state radiation and beamstrahlung effects, and the most important QCD corrections in an approximate (nai ve) form. We compare such a complete approach with the production x de cay approximation and we suggest that in many physical studies the for mer is needed. (C) 1998 Elsevier Science B.V.