respecting the Ward-Takahashi identity. This suggests that it is worthwhile exploring the importance of accurately modelling the quark-gluon vertex, as well as the gluon propagator, when studying the analytic structure of the quark propagator.

In a recent development, the DSE technique has been extended to the realm of heavy quarks [@BL97; @DL97] in a way inspired by heavy quark effective theory (HQET) [@N94]. The purpose of this exercise was twofold. Firstly, if one acknowledges the success of the DSE technique in the light quark sector, it is clear that the dynamics of confined particles is driven by non-perturbative dynamical self dressing. In HQET, non-perturbative self dressing and the detailed analytic structure of the heavy quark propagator are largely ignored. It is important to know whether this is justified, or whether the successes of HQET are purely fortuitous. Secondly, one has the hope that an accurate determination of the heavy quark propagator will eventually prove useful for building phenomenological models of heavy quark hadrons.

In ref. [@BL97] a preliminary attempt is made to calculate the spectrum of heavy quark–light antiquark mesons by using the combination of rainbow DSE and ladder Bethe-Salpeter equation (BSE). It is found that, within the limitations of 