Why we do not consider the divergence due to mass-shell in QED?

[ndung200790]

Please teach me this:
Why we do not consider the divergences in loops in QED when p^{2}→m^{2} but only consider the soft photon when k^{2}→0(IR divergence) and UV divergence?
Thank you very much in advance.

 

[tom.stoer]

p²-m² is always regulated via the "iε-Term" and is evaluated via the Cauchy contour integral

 

[ndung200790]

Why we have not the same consideration when m=0?

 

[ndung200790]

Sorry,Now I have understood.Applying Cauchy's theorem when m=0(so k^{2}→0)
we have divergence(IR divergence)