Lepton flavour violating signals of gauge bosons Z′ at future e+e- colliders

Many models, such as topcolour-assisted technicolour (TC2) models and flavour-universal TC2 models, predict the existence of extra U (1) gauge bosons Z', which couple preferentially to the third generation. The lepton flavour violating (LFV) signals of these new particles at the future e(+)e(-) colliders (LCs) are discussed by calculating their contributions to the LFV process e(+)e(-) --> mutau. We calculate the cross section of this process and discuss its dependence on the beam polarization. The ratio of the signal over the square root of the background (S/rootB) is also calculated. The results show that the LFV signals of the gauge bosons Z' may be detected at the future LC experiments.