The theory of scattering consists in studying the collision also called dispersion, between two or more particles. We will study the simplest case of the collision between two particles without spin. It is assumed that the interaction between the two particles is described by a potential energy which V ( x → 2 - x → 1 ) $$ V(\vec{x}_{2} - \vec{x}_{1} ) $$ https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9781351166287/b7abbdf6-7138-4590-9fd1-9bfc5c5d6120/content/math14_1.tif"/>