Fig. \[fig:quarkgluonvertex\_components\_msp\], we would conclude that the operator in seems to be the most important one by far. We find, however, that also the operator in is very important for the value of the quark propagator mass function. This is explained by the fact that breaks chiral symmetry and contributes therefore directly to the quark mass function.

Quark propagator
----------------

Next we discuss our solution for the quark propagator, see Fig. \[fig:quarkpropagator\_msp\], for an earlier study see e.g. [@Fischer:2003rp], and the effect of different quark-gluon interactions. We find very convincing agreement with results obtained in lattice QCD in the quenched approximation [@Bowman:2005vx], that are shown with dimensionful quantities rescaled by a factor of $0.91$ to match the scale of [@Sternbeck:2006cg] and [@Fischer:2008uz; @FP]. However, some care is necessary when comparing our propagator to the lattice results, since the quenched approximation in lattice simulations sets the fermion determinant to unity, whereas we just used a quenched gluon propagator.

Apart from the classical tensor structure, the most important contribution to the quark propagator stems from the tensor structures $\tfrac{1}{2}{\cal T}^{(5)}_{\bar q A q}+{\cal T}^{(7)}_{\bar q A q}$ for $Z_q(p)$, and $\tfrac{1}{2}{\cal T}^{(2)}_{\bar q A q}+{\cal
  T}^{(4)}_{\bar q A q}$ for $M_q(p)$, where 