Flavor SU(4) breaking between effective couplings

TL;DR

This paper uses Dyson-Schwinger equations to evaluate SU(4) flavor symmetry relations in meson couplings, revealing significant underestimation of DρD coupling compared to SU(4) predictions, while SU(3) symmetry remains relatively accurate.

Contribution

It provides a consistent, QCD-based analysis of flavor symmetry breaking effects in meson couplings, especially highlighting the limitations of SU(4) symmetry.

Findings

SU(3) flavor symmetry is accurate within 20%.

SU(4) relations underestimate DρD coupling by a factor of five.

The framework incorporates both light and heavy quarks coherently.

Abstract

Using a framework in which all elements are constrained by Dyson-Schwinger equation studies in QCD, and therefore incorporates a consistent, direct and simultaneous description of light- and heavy-quarks and the states they constitute, we analyze the accuracy of SU(4)-flavor symmetry relations between {\pi}{\rho}{\pi}, K{\rho}K and D{\rho}D couplings. Such relations are widely used in phenomenological analyses of the interactions between matter and charmed mesons. We find that whilst SU(3)-flavor symmetry is accurate to 20%, SU(4) relations underestimate the D{\rho}D coupling by a factor of five.