Double-logarithmic (Sudakov) asymptotics at the theory of electroweak interactions

Abstract

Accounting for double-logarithmic contributions to high-energy (>> 100 GeV) e^+ e^- annihilation into a quark or a lepton pair in the kinematics where the final particles are colinear to the e^+e^- beams leading to a sizable difference between the forward and backward scattering amplitudes, i.e. to the forward-backward asymmetry. When the annihilation is accompanied by emission of n electroweak bosons in the multi-Regge kinematics, it turns out that the cross sections of the photon and Z production have the identical energy dependence and asymptotically their ratio depends only on the Weinberg angle (is equal to tan^{2n} theta_W) whereas the energy dependence of the cross section of the W production is suppressed by factor s^{-0.4} compared to them.