Neutral Pion Electroproduction on the Proton near Threshold

Abstract

The neutral pion electroproduction on the proton is considered in the framework phenomenological model based on the PCAC, current algebra with hard pions and chiral symmetry breaking interaction. The s- wave differential cross-section of the electroproduction of neutral pions off protons near the threshold is predicted as function photon momentum transfer squared $k^2$ . The s- wave multipoles $Re{E}_{0+}$ and $Re{L}_{0+}$ as function of the energy of the ${\pi }^{0}p$- system are given for the small $k^2$ and . The results are compered with the experiment. It is shown the significant role of the explicit chiral symmetry breaking.

Comments: 28 pages, 5 Postscript figures, Latex