Insights into the Quark–Gluon Vertex from Lattice QCD and Meson Spectroscopy

By comparing successful quark–gluon vertex interaction models with the corresponding interaction extracted from lattice-QCD data on the quark’s propagator, we identify common qualitative features which could be important to tune future interaction models beyond the rainbow ladder approximation. Clearly, a quantitative comparison is conceptually not simple, but qualitatively the results suggest that a realistic interaction should be relatively broad with a strong support at about 0.4–0.6 GeV and infrared-finite.