The form factor of the transition gamma gamma * pi^0

Abstract

A simple method is used to extrapolate the form factor for the process gamma* gamma *--->pi^0 when two virtual photons produce a pi ^0 from the region of large spacelike photon virtualities to the experimentally accessible case when one of the photons is real. The method is also applied to the study of the axial anomaly and omega -rho -pi coupling and to the pion charge and charge radius. The results compare favourably with the experimental measurements.

Comments: 9 pages, 1 eps figure