On power corrections to event shapes

TL;DR

This paper reviews recent advances in understanding power corrections in perturbative QCD, focusing on event shapes in e+ e- annihilation, and discusses how soft gluon effects and shape functions help estimate nonperturbative corrections.

Contribution

It provides a concise overview of the factorization and resummation techniques for power corrections in event shape observables, highlighting progress towards modeling nonperturbative effects.

Findings

Resummation of soft gluon effects clarifies perturbation theory limitations.

Shape functions can incorporate nonperturbative corrections.

Theoretical models are advancing towards a comprehensive understanding of nonperturbative QCD effects.

Abstract

Recent work on the theme of power corrections in perturbative QCD is briefly reviewed, with an emphasis on event shapes in e+ e- annihilation. The factorization of soft gluon effects is the main tool: it leads to resummation, and thus highlights the limitations of perturbation theory, pointing to nonperturbative corrections whose size can be estimated. Power corrections can be resummed into shape functions, for which QCD--based models are available. Theoretical progress is closing in on the nonperturbative frontier.