Two-loop QED radiative corrections to the decay pi0 -> e+ e- : The virtual corrections and soft-photon bremsstrahlung

Understand

This paper is devoted to the two-loop QED radiative corrections to the decay pi0 -> e+ e-.

• We compute the virtual corrections without using any approximation and we take into account all the relevant graphs with the inclusion of those omitted in the previous approximative calculations.
• The bremsstrahlung is then treated within the soft photon approximation.
• We concentrate on the technical aspects of the calculation and discuss in detail the UV renormalization and the treatment of IR divergences within the dimensional regularization.