FORM FACTORS AND IMPACT FACTORS IN HIGH-ENERGY SCATTERING

In this paper, we study the general properties of the impact factor. In particular, the fourth-order impact factor for the electron is shown to exist and is explicitly worked out. This implies that the sum of the corresponding sixth-order amplitudes for processes like electron-electron scattering satisfies the impact-factor representation. We also find that, in both the second and the fourth order, the impact factor is proportional to the electromagnetic form factor. An interesting relation between the impact factor and the form factor is then shown to hold generally. These arguments are next extended to scalar mesons and the same conclusions are reached. Considerations on the impact factor in higher orders are also made. © 1969 The American Physical Society.