Pion form factor in the Kroll-Lee-Zumino model

The renormalizable Abelian quantum field theory model of Kroll, Lee, and Zumino is used to compute the one-loop vertex corrections to the tree-level, vector meson dominance pion form factor. These corrections, together with the known one-loop vacuum polarization contribution, lead to a substantial improvement over vector meson dominance. The resulting pion form factor in the spacelike region is in excellent agreement with data in the whole range of accessible momentum transfers. The timelike form factor, known to reproduce the Gounaris-Sakurai formula at and near the rho-meson peak, is unaffected by the vertex correction at order O(g_ρππ²).