Calculation of cross sections in Lorentz-violating theories

We revisit, starting from the first principles, the calculation of scattering cross sections in theories with violation of the Lorentz invariance. Our approach takes into account all information about the Lagrangian of the theory and is applicable to the case of Lorentz violation by higher-dimension operators. As an illustration, we consider spinor electrodynamics with Lorentz violating operators of dimension four and six that preserve CPT, …