  We compute nucleon and Delta elastic and transition form factors, and compare
predictions made using a framework built upon a Faddeev equation kernel and
interaction vertices that possess QCD-like momentum dependence with results
obtained using a vector-vector contact-interaction. The comparison emphasises
that experiment is sensitive to the momentum dependence of the running
couplings and masses in the strong interaction sector of the Standard Model and
highlights that the key to describing hadron properties is a veracious
expression of dynamical chiral symmetry breaking in the bound-state problem.
Amongst the results we describe, the following are of particular interest:
$G_E^p(Q^2)/G_M^p(Q^2)$ possesses a zero at $Q^2=9.5GeV^2$; any change in the
interaction which shifts a zero in the proton ratio to larger $Q^2$ relocates a
zero in $G_E^n(Q^2)/G_M^n(Q^2)$ to smaller $Q^2$; and there is likely a value
of momentum transfer above which $G_E^n>G_E^p$. Regarding the
$\Delta(1232)$-baryon, we find that, inter alia: the electric monopole form
factor exhibits a zero; the electric quadrupole form factor is negative, large
in magnitude, and sensitive to the nature and strength of correlations in the
$\Delta(1232)$ Faddeev amplitude; and the magnetic octupole form factor is
negative so long as rest-frame P- and D-wave correlations are included. In
connection with the N-to-Delta transition, the momentum-dependence of the
magnetic transition form factor, $G_M^\ast$, matches that of $G_M^n$ once the
momentum transfer is high enough to pierce the meson-cloud; and the electric
quadrupole ratio is a keen measure of diquark and orbital angular momentum
correlations.
