Searches for and separation of effects of lepton and boson mixing at linear e+e- colliders

Within models involving an extended gauge sector, a method is proposed for separating signals induced by new neutral gauge bosons and exotic leptons in electron-positron annihilation into a pair of W± bosons. This method is based on use of polarization observables for various versions of initial and final polarization states. It is shown that, in the case of specified final polarization states, experiments with longitudinally polarized e+e- beams at next-generation colliders will make it possible not only to obtain constraints on individual parameters of mixing of ordinary and exotic leptons, as well as on the angle of Z-Z' mixing, but also to toughen considerably the constraints that are expected from the corresponding experiments with unpolarized particles