Electromagnetic corrections to leptonic decay rates of charged pseudoscalar mesons: finite-volume effects

Understand

In Carrasco et al.

• we have recently proposed a method to calculate $O(e^2)$ electromagnetic corrections to leptonic decay widths of pseudoscalar mesons.
• The method is based on the observation that the infrared divergent contributions (that appear at intermediate stages of the calculation and that cancel in physical quantities thanks to the Bloch-Nordsieck mechanism) are universal, i.e.
• depend on the charge and the mass of the meson but not on its internal structure.