 On shell renormalization scheme

The on-shell renormalization scheme fixes masses at physical propagator poles, fixes field normalizations by pole residues, and fixes couplings through amplitudes evaluated with external particles on their mass shells.

The on-shell renormalization scheme is a method used in quantum field theory to handle the divergences that arise in the calculation of physical quantities. In this approach, the parameters of a quantum field theory, such as mass and coupling constants, are renormalized in a way that relates the theoretical predictions directly to measurable physical quantities, specifically the observables associated with actual particles.