Pion-Pion Interaction in Electromagnetic Processes

The correction to the photon propagator due to the emission of a virtual pion pair is evaluated taking into account the effect of the strong pion-pion interaction in the $J=1\mathrm{}$, $T=1\mathrm{}$ state of the pions recently discussed by several authors. Results are given for different sets of parameters describing the pion form factor, and the possibility of investigating the structure of the form factor by means of electron-electron and electron-positron collision experiments is studied.