# Mathematical Physics Seminar

**Abstract: **We apply a covariant approach denoted by Covariant Spectator Theory (CST) to the heavy-light and heavy-heavy quark meson spectrum. We investigate the consequences of a general effective quark-anti-quark interaction containing Lorentz scalar, pseudoscalar, and vector contributions, with the goal of reproducing QCD phenomenology. The interaction kernel satisfies chiral symmetry. The obtained meson mass spectra agrees very well to the experimental data, with just very few fitted parameters. In general, we found little dependence of the parameters of the models on the meson sector used in the fitting procedure. Only the weight of the Lorentz vector component of the confinement potential cannot be fixed with certainty from the fits. We also calculate the mesons wave functions. Effects on the spectrum and the wave functions from varying the constituent quark mass and the Lorentz structure of the confining potential are discussed.