Conformal or confining -- results from lattice gauge theory for higher-representation gauge theories

TL;DR

This paper investigates whether certain higher-representation gauge theories exhibit infrared fixed points, indicating conformal behavior, by calculating the running coupling nonperturbatively in SU(2), SU(3), and SU(4) gauge theories.

Contribution

It provides the first nonperturbative calculations of the running coupling in these higher-representation gauge theories to identify potential infrared fixed points.

Findings

Some theories show signs of approaching an infrared fixed point

Results suggest possible conformal behavior in certain gauge theories

Nonperturbative data complements perturbative predictions

Abstract

We have calculated the running coupling in SU(2), SU(3), and SU(4) gauge theories to see whether they have infrared fixed points. An infrared fixed point means no confinement: It means that the long-distance physics is conformal, without a mass scale and indeed without a particle spectrum. All these theories run slowly in perturbation theory, so a nonperturbative determination is interesting.