QCD Power Corrections from a Simple Model for the Running Coupling

TL;DR

The paper introduces a simple analytic model for the QCD running coupling at low scales to study non-perturbative power corrections. It analyzes a toy observable F_{p,q}(Q) and uses an infrared matching scheme to separate perturbative and non-perturbative contributions, encoding IR effects in moments F_{p,q}(μ_I). Compared with renormalon-based estimates, the infrared matching approach yields more consistent power corrections within the model and demonstrates how universal IR behaviour can be reconciled with higher-order perturbative inputs. The work provides a controlled framework for evaluating power corrections and suggests future refinements, including two-loop running and flavor thresholds, while highlighting the non-universal nature of renormalon prescriptions at higher orders.

Abstract

A simple parametrization of the QCD running coupling at low scales is introduced and used to illustrate various schemes for the estimation of non-perturbative power corrections. The `infrared matching' scheme proposed earlier gives satisfactory results when combined with next-to-leading (or higher) order perturbative predictions. Estimates based on renormalons are shown to be inconsistent with universal behaviour of the running coupling.