Feynman Amplitude and Scattering Cross-Section for a Toy Theory

exchange particle mass 

choose plot

amplitude

differential cross section

Amplitude and differential cross sections for two-body scattering

(A+AA+A)

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

m

of the exchanged virtual particle and see how the curves behave.

The general relation between differential cross section and Feynman amplitude is:

2

σ

Ω

=

2

ℏ

64

2

π

s

p

f

p

i

ℳ

fi

.