Regularizing the divergent structure of light-front currents - art. no. 074014

The divergences appearing in the (3+1)-dimensional ferrnion-loop calculatio ns are often regulated by smearing the vertices in a covariant manner. Perf orming a parallel light-front calculation, we corroborate the similarity be tween the vertex-smearing technique and the Pauli-Villars regularization. I n the light-front calculation of the electromagnetic meson current, we find that the persistent end-point singularity that appears in the case of poin t vertices is removed even if the smeared vertex is taken to the limit of t he point vertex. Recapitulating the current conservation, we substantiate t he finiteness of both valence and nonvalence contributions in all component s of the current with the regularized bound-state vertex. However, we stres s that each contribution, valence or nonvalence, depends on the reference f rame even though the sum is always frame independent. The numerical taxonom y of each contribution including the instantaneous contribution and the zer o-mode contribution is presented in the pi, K, and D-meson form factors.