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

To the special case of Bhabha scattering we extend the “Z-peak subtracted” representation previously applied to e⁺e^-→ff̅ (f≠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 in a search for 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 information that can be derived from the other e⁺e^- annihilation processes, both at present (CERN LEP2) and at future colliders. This shows that the role of Bhabha scattering in this respect can be quite relevant.