Bound States and Dispersion Relations

Abstract
A vertex closely related to the Bethe-Salpeter amplitude is discussed in the one meson exchange approximation by dispersion theory methods. Both scalar and spinor cases are treated. The relation between anomalous thresholds and the Schrödinger equation is discussed in some detail. It is shown that dispersion methods can be used to determine bound state parameters. An estimate is made of the asymptotic (DS) ratio for the deuteron.