CROSSING-SYMMETRIC BOOTSTRAP AND EXPONENTIALLY FALLING FORM FACTORS

It is shown that form factors with the asymptotic behavior F(t)∼exp(-|t|12) are a consequence of the nonlinear bound-state equation for the wave function in the crossing-symmetric bootstrap model. This nonlinear equation incorporates the notion that the constituent particles are themselves composite. The result is obtained both from the Schrödinger equation and the Bethe-Salpeter equation; in the latter case, it is argued that the result should be valid for a wide class of interaction kernels. © 1968 The American Physical Society.