  The pion structure in Minkowski space is described in terms of an analytic
model of the Bethe-Salpeter amplitude combined with Euclidean Lattice QCD
results for the running quark mass. In the present work, a pion model
previously proposed, which allows for a Nakanishi integral representation, is
studied in order to verify the sensitivity of the pion electromagnetic form
factor to small variations of the quark self-energy. In addition, we extend the
previous work, providing the Nakanishi integral representation for the
invariants associated with a decomposition of the pion Bethe-Salpeter
amplitude.
