The soft parton expansion in perturbative QCD

Abstract

The master project investigates factorization theorems and their application on various infrared divergent scenarios in physics either caused by virtual or by real divergent momenta. Specifically it is divided in three parts: The first part entails examining the QCD perturbation series for a number of amplitudes and cross sections, and establishing a factorization theorem in terms of jet-, soft and hard functions to nextto-leading power in the soft parton expansion. This also involves testing particular matrix element definitions of the new jet functions involved. Part two is an analysis of the higher twist contributions in inclusive DIS, providing detailed analytical calculations of the procedure and focusing on the special propagator technique and leads to Part third’s effort to apply the latter to the former QCD processes.