Calculation of the scattering amplitude in the Regge representation
An analysis of the Regge representation of the elastic scattering amplitude is given. The background term is discussed in detail showing that, for large-angle scattering, its contribution is non-oscillatory and represents reflection from the core of a potential. It is shown that the direct reflection term cannot be ignored, although in low-energy collision the Regge pole contribution is dominant. However, in high-energy collisions, it may be the sole contribution to the large-angle differential cross section. This is confirmed in one example, with the explicit calculation of the Regge-pole and background term contributions to the scattering amplitude. The background term is dominant in the forward direction, representing diffraction and forward glory. On the other hand, the Regge-pole contribution can be neglected in first order.