On Proton and Delta Wave Functions

Physical wave functions for the nucleon and the $\Delta^{+}$ isobar are presented, which unify the best features of previous models. With these wave functions we can calculate elastic form factors and the decays of the charmonium levels ${}^{3}S_{1}$, ${}^{3}P_{1}$, ${}^{3}P_{2}$ into $p\bar p$ in agreement with the data. A striking scaling behavior between $R=|G_{\text{M}}^{\text{n}}|/G_{\text{M}}^{\text{p}}$ and the coefficient $B_{4}$ of the Appell polynomial decomposition of the nucleon distribution amplitude is found; the implications for elastic nucleon cross sections are discussed.