Three-Pion Contribution to the Electromagnetic Structure of the Nucleon

In this paper the contribution of three pions to the scalar electromagnetic form factors of the nucleon are computed by using the fixed source meson theory without rescattering corrections. The ($\gamma , 3\pi$) interaction is taken phenomenologically as a point interaction. It is shown that for those values of the ($\gamma , 3\pi$) coupling constant compatible with photoproduction experiments, the experimental charge distribution could be roughly fitted with a cutoff in the dispersion integral of the order of 7 pion masses.