Prof. Dr. Stefan Dittmaier

Owing to the soft/collinear exchange or emission of electroweak gauge bosons, electroweak radiative corrections grow very large at high energies, reaching several 10% already in the TeV energy range. For real emission effects, the logarithmic enhancement of these corrections is controlled by splitting functions, similar to the situation in QED and QCD. In this talk, we report on a calculation of the lowest-order splitting functions in a generic spontaneously broken gauge theory with scalars, fermions, and vector bosons. Working in the broken phase of the theory, we derive quasi-collinear factorization formulas that properly take into account all mass effects as well as polarization. The main complication of the calculation, which lies in the presence of mass-singular terms in the polarization vectors of longitudinal vector bosons, is overcome using gauge invariance and Ward identities as guiding principle.