Exchange of hard and soft quanta in high-energy scattering

In the framework of the functional approach in field theory, a method is proposed for obtaining the scattering amplitude of two particles in the case when a finite number of “hard” and an infinite number of “soft” quanta are exchanged. This approach to the calculation of the large-angle scattering amplitude leads to the appearance of form factors of interacting particles, which agrees with the conjecture of Yang and Wu concerning the role of elastic form factors in high-energy scattering.