Off-shell pion electromagnetic form factors in chiral perturbation theory

The electromagnetic form factors of the pion play a role in investigations of various electromagnetic interactions. We calculate the off-shell pion form factors using chiral perturbation theory, which is the effective theory for QCD at low energies. Chiral perturbation theory has previously been used to calculate the on-shell form factors. The formalism is here described, and it is modified to accomodate possible off-shell contributions to Green functions in the pseudoscalar meson sector. We find that in addition to the phenomenological constant 'L₉' associated with the pion charge radius, another phenomenological constant enters the electromagnetic form factor ƒπ⁺. This constant scales a contribution that is linear in (p² - mπ²) for either of the pions at the vertex.Science, Faculty ofPhysics and Astronomy, Department ofGraduat