Scattering Detailed Balance

physicskinematicsparticle physicsscatteringFeynman diagramscetztikz

A simple diagram representing a scattering process in particle physics, where two incoming particles with momenta $p$ and $k$ interact and produce two outgoing particles with momenta $p'$ and $k'$. The principle of detailed balance states that at equilibrium, each scattering process is in equilibrium with its reverse process.