Calculational Techniques in Perturbative QCD: The Drell-Yan Process

A detailed calculation of the O(ff s ) Drell-Yan reaction in the dimensional regularization scheme is presented with special emphasis on the real corrections. The concept of factorization and renormalization of parton distribution functions is discussed in connection with the O(ff s ) corrections. Some useful formulae for calculating cut diagrams and integrals in n dimensions are collected in an extensive appendix. Talk given at the Colloquium of the Gradiuertenkolleg "Theoretische Elementarteilchenphysik", Hamburg University y Supported by Bundesministerium fur Forschung und Technologie, Bonn, Germany, under Contract 05 7 HH 92P (0), and by EEC Program Human Capital and Mobility through Network Physics at High Energy Colliders under Contract CHRX--CT93--0357 (DG12 COMA). 1 Introduction The answer to the question "What is a hadron?" will depend on the scale at which the hadron is observed. At the atomic scale the hadrons behave pointlike. At the strong interaction scale of the o..