%0 Journal Article
%T The Quark-Photon Vertex and the Pion Charge Radius
%A P. Maris
%A P. C. Tandy
%J Physics
%D 1999
%I arXiv
%R 10.1103/PhysRevC.61.045202
%X The rainbow truncation of the quark Dyson-Schwinger equation is combined with the ladder Bethe-Salpeter equation for the dressed quark-photon vertex to study the low-momentum behavior of the pion electromagnetic form factor. With model gluon parameters previously fixed by the pion mass and decay constant, the pion charge radius $r_\pi$ is found to be in excellent agreement with the data. When the often-used Ball-Chiu Ansatz is used to construct the quark-photon vertex directly from the quark propagator, less than half of $r_\pi^2$ is generated. The remainder of $r^2_\pi$ is seen to be attributable to the presence of the $\rho$-pole in the solution of the ladder Bethe-Salpeter equation.
%U http://arxiv.org/abs/nucl-th/9910033v1