Relativistic bound-state form factors in a solvable (1 + 1)-dimensional model including pair creation

Abstract

The relativistic two-body bound-state form factor, recently calculated by Mankiewicz and Sawicki from a light-front formula involving analytic solutions to the Weinberg equation in a (1 + 1)-dimensional model field theory, is compared with the form factor obtained from the Mandelstam formula using analytic solutions to the corresponding Bethe-Salpeter equation. The results are different, since the former formula does not include the contribution of pair-creation diagrams which are included in the latter. When the pair-creation diagrams are included in the light-front formula in 1 + 1 dimensions, both approaches yield a numerically identical form factor, not having the strange properties described by Mankiewicz and Sawicki.