Consistent treatment for pion form factors in spacelike and timelike regions - art. no. 034011

We write down some relevant matrix elements for the scattering and decay pr ocesses of the pion by considering a quark-meson vertex function, The pion charge and transition form factors F-pi, F-pi gamma, and F-pi gamma* are ex tracted from these matrix elements using a relativistic quark model on the light front, We find that the form factors F-pi and F-pi gamma in the space like region agree well with experiment. Furthermore, the branching ratios o f all observed decay modes of the neutral pion that are related to the form factors F-pi gamma and F-pi gamma* in the timelike region are consistent w ith the data as well. F-pi in the timelike region, which deals with the non valence contribution, is also discussed.