MASS BOUNDS ON THE EXTRA NEUTRAL VECTOR BOSONS AT FUTURE E- COLLIDERSWITH POLARIZED BEAMS(E)

After the example of the extended electroweak models, which predict th e existence of the heavy neutral vector boson Z', we discuss, for the e+ e- linear colliders of the new generation, the possibilities of sea rching for the extra boson effects provided that various configuration s of the beam polarizations will be available. For the most popular mo dels [E6-superstring-inspired, LR- and Y(Y(L))-composite models] we sh ow that realization of the specific beam polarizations can substantial ly enhance the experiment sensitivity to the Z' signal in comparison w ith the case of the unpolarized beams.