The role of the running coupling constant in the unveiling of the hadronic structure

TL;DR

This paper explores how the non-perturbative behavior of the QCD running coupling constant influences the understanding of hadronic structure and improves the connection between models and experimental data.

Contribution

It introduces a non-perturbative generalization of the QCD running coupling to better match models with experimental data in hadronic physics.

Findings

Enhanced understanding of the coupling constant's freezing behavior.

Improved matching of non-perturbative models to experimental data.

Insights into the validity of perturbative QCD in hadronic models.

Abstract

One of the main open questions in physics is the understanding of the internal structure of the strongly interacting particles, or hadrons. It is still a challenge to describe consistently the dynamics of scattering processes and hadronic structure at moderate energy scales. The study of Parton Distribution Functions (PDFs) sets a connection between the perturbative and non-perturbative worlds, through the following scheme: one builds models consistent with QCD in a moderate energy range, PDFs are evaluated in these models, and, finally, the scale dependence of these distributions is studied. In these proceedings, we revisit the standard procedure to match non-perturbative models to perturbative QCD, using experimental data. The strong coupling constant plays a central role in the QCD evolution of parton densities. We will extend this procedure with a non-perturbative generalization of the QCD running coupling and use this new development to understand why perturbative treatments are working reasonably well in the context of hadronic models. Vice versa, this new procedure broadens the ways of analyzing the freezing of the running coupling constant.