The general formalism of some scattering processes involving photons

Abstract

By correctly defining the polarization vectors of photons and the spinors for particles of spin 1 2 according to the prescription of Jacob and Wick, we show how to obtain the partial wave expansions of the invariant reaction amplitudes for the processes γ+N→ π+N, γ+N→ γ+N and γ+γ→ N+ N . No specific representation of the Dirac matrices is necessary.