  In the present work, we describe a model for the pion based on an analytic
expression for the Bethe-Salpeter (BSA) amplitude, combined with some
ingredients from Lattice QCD calculations. The running quark mass function $M
(p^2)$, used here, reproduces well the results of Lattice QCD calculations. The
analytical form of the running quark mass function contains a single time-like
pole, which implies in time-like poles of the dressed quark propagator. Such a
form allows to build the weight functions, $G_i(\gamma,z)$, for the Nakanishi
integral representation of each scalar function, $\chi_{i}(k,p)$, appearing in
the decomposition of the Bethe-Salpeter amplitude in terms of Dirac operators,
Such scalar amplitudes can also be used to obtain the pion valence light-front
wave function.
