Difference of Nucleon and Pion Electromagnetic Radii

Abstract

The nucleon isovector Pauli radius $〈{R_{2V}}^2〉$ is calculated, using sidewise dispersion relations, to be significantly larger than the predictions of $\rho$ dominance, in accord with observation. It is also predicted that $〈{R_{2V}}^2〉$ is significantly larger than the pion charge radius $〈{R_{\pi }}^2〉$. Elastic scattering of pions from electrons at very high energies (viz. Serpukhov) will give a clear confrontation with this prediction.