Electromagnetic Pion Form Factor and Neutral Pion Decay Width

Abstract

The electromagnetic pion form factor, $F_{\pi }(q^2)$, is calculated for spacelike-$q^2$ in impulse approximation using a confining quark propagator, $S$, and a dressed quark-photon vertex, ${\Gamma }_{\mu }$, obtained from realistic, nonperturbative Dyson-Schwinger equation studies. Good agreement with the available data is obtained for $F_{\pi }(q^2)$ and other pion observables, including the decay ${\pi }^0\to \gamma \gamma$. This calculation suggests that soft, nonperturbative contributions dominate $F_{\pi }(q^2)$ at presently accessible~$q^2$.

Comments: 25 pages, LaTeX, elsart.sty, 5 figures, To appear in Nucl. Phys. A