Fractional electric charge and quark confinement

TL;DR

This paper explores how fractional electric charges of quarks relate to a global center symmetry in the Standard Model and investigates its potential role in quark confinement through a 2-color model with dynamical Wilson quarks.

Contribution

It introduces an analysis of a $Z_6$-like center symmetry involving electromagnetic and color phases, and studies its implications for quark confinement.

Findings

Identification of a $Z_6$-like symmetry in a 2-color model

Potential relevance of topological defects to confinement

Insights into the interplay of electromagnetic charge and color confinement

Abstract

Owing to their fractional electric charges, quarks are blind to transformations that combine a color center phase with an appropriate electromagnetic one. Such transformations are part of a global $Z_6$-like center symmetry of the Standard Model that is lost when quantum chromodynamics (QCD) is treated as an isolated theory. This symmetry and the corresponding topological defects may be relevant to non-perturbative phenomena such as quark confinement, much like center symmetry and ordinary center vortices are in pure SU($N$) gauge theories. Here we report on our investigations of an analogous symmetry in a 2-color model with dynamical Wilson quarks carrying half-integer electric charge.