Functional integration and Regge-eikonal representation of the scattering amplitude

In the scalar $g\psi^2\varphi$-model, the functional integration method is used in the straight-line path approximation to obtain a Regge-eikonal representation for the scattering amplitude of highenergyparticles. To this end all possible ladder diagrams with “many-tower” exchange are summed in the framework of the given approximation.