Feynman Amplitude and Scattering Cross-Section for a Toy Theory
Amplitude and differential cross sections for two-body scattering are calculated using a second-order Feynman diagram of a toy theory (no spin, no charge, no polarization, no color) in the center of mass system. The graphs show the Feynman amplitude ℳ and the differential cross section dσ/dΩ as functions of the scattering angle θ, in radians. You can vary the mass of the exchanged virtual particle and see how the curves behave.
The general relation between differential cross section and Feynman amplitude is: .