Z-peak subtracted representation of Bhabha scattering and search for new physics effects

Abstract

We extend to the special case of Bhabha scattering the "Z-peak subtracted" representation previously applied to e+e- to f f(bar) (f different from e). This allows us to analyze the process at any energy while imposing in an automatic way the constraints set by high precision measurements at the Z peak. The procedure turns out to be particularly convenient for the search of a certain class of new physics effects at variable energy. A few examples are considered and the information thus obtained is combined with the corresponding one that can be derived from the other e+e- annihilation processes, both at present (LEP2) and at future colliders. This shows that the role of Bhabha scattering in this respect can be quite relevant.