Restoring the equivalence between the light-front and manifestly covariant formalisms

We discuss a treacherous point in light-front dynamics (LFD) which should be taken into account to restore complete equivalence with the manifestly covariant formalism. We present examples that require an inclusion of the arc contribution in the light-front energy contour integration in order to achieve the equivalence between the LFD result and the manifestly covariant result.

Figure 1

The self-energy diagram.

Figure 2

The triangle diagram.