Hadronization

Abstract

Hadronization corrections to the predictions of perturbative QCD are reviewed. The existing models for the conversion of quarks and gluons into hadrons are summarized. The most successful models give a good description of the data on $e^+e^-$ event shapes and jet fragmentation functions, and suggest that the dominant hadronization effects have a $1/Q$ dependence on the hard process energy scale $Q$. In several cases the $1/Q$ terms can be understood in terms of a simple longitudinal phase-space model. They can also be inferred by relating non-perturbative renormalon effects to the infrared cutoff dependence of perturbative contributions.