Radiative Corrections of Order a Za

1 Correction Induced by the Radiative Insertions in the Electron Line 

This correction is generated by the sum of all possible radiative insertions in the electron line in Fig. 3.9. In the approach described above one has to calculate the electron factor corresponding to the sum of all radiative corrections in the electron line, make the necessary subtraction of the leading infrared asymptote, insert the subtracted expression in the integrand in (3.33), and then integrate over the exchanged momentum. This leads to the result 

2 Correction Induced by the Polarization Insertions in the External Photons 

The correction of order a Za) induced by the polarization operator insertions in the external photon lines in Fig. 3.10 was obtained in [40, 41, 42] and may again be calculated in the skeleton integral approach. We will use the simplicity of the one-loop polarization operator, and perform this calculation in more detail in order to illustrate the general considerations above. For calculation of the respective contribution one has to insert the polarization operator in the skeleton integrand in (3.33) 

Of course, the skeleton integral still diverges in the infrared after this substitution since 

---

Radiative Correction of Order a(Za) r )m to the Finite Size Effect... 

---