VACUUM POLARIZATION EFFECTS OF NEW PHYSICS ON ELECTROWEAK PROCESSES

The effects of new physics on vacuum polarization corrections to electroweak processes can in general be parametrized in terms of six real constants, in the limit of neglecting terms which vanish for LAMBDA --> infinity, with LAMBDA being the scale of new physics. Three of these parameters can be reabsorbed in the definitions of alpha, G(F) and m(Z), while the remaining three are observables. On the basis of simple models, it is shown that all three can be important and should be kept in a model-independent analysis of the data. This is equivalent to treating DELTA-r, DELTA-rho and sbar2w (an effective sin2-theta-w for on-shell Z couplings) as independent observables. By now available data allow a separate model-independent determination of these quantities. Implications for technicolour and supersymmetric models and anomalous gamma-WW or ZWW couplings are discussed.