Flavor SU(4) breaking between effective couplings
  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. 
Bruno El-Bennich, Gast\~ao Krein, Lei Chang, Craig D. Roberts and   David J. Wilson
nucl-th hep-ex hep-lat hep-ph nucl-ex