  We analyze the off-shell scattering amplitudes in the framework of the
light-front perturbation theory. It is shown that the previously derived
recursion relation between tree level off-shell amplitudes in this formalism
actually resums whole classes of graphs into a Wilson line. More precisely, we
establish a correspondence between the light-front methods for the computation
of the off-shell amplitudes and the approach which makes use of the matrix
elements of straight infinite Wilson lines, which are manifestly gauge
invariant objects. Furthermore, since it is needed to explicitly verify the
gauge invariance of light-front amplitudes, it is demonstrated that the Ward
identities in this framework need additional instantaneous terms in the
light-front graphs.

High Energy Physics - Phenomenology