Power Corrections to the Parton Model in QCD

Abstract We calculate the power corrections to deep inelastic lepton-hadron scattering in QCD in terms of Feynman graphs, introducing a “transverse basis” of parton correlation functions as a useful language which, although unrelated to observable transverse momenta effects, may help physical intuition. The method is applicable to other hand scattering processes. In that framework we stress the relationship to the naive parton model with intrinsic transverse momentum and show how the average intrinsic transverse momentum squared of that model is modified in the interacting theory.