FORM-FACTOR PI(0)-]GAMMA-ASTERISK-ASTERISK AT DIFFERENT PHOTON VIRTUALITIES(GAMMA)

The pi(0) gamma gamma vertex for virtual photons of squared masses q(1 )(2) and q(2)(2) plays a vital role in several physical processes; for example for q(1)(2) < 0, q(2)(2) < 0, in the two-photon physics react ion e(+)e(-) --> e(+)e(-) pi(0), and for q(1)(2) > 0, q(2)(2) > 0, in the annihilation process e(+)e(-) --> pi(0)l(+)l(-). It is also of int erest because of its link to the axial anomaly. We suggest a new appro ach to this problem. We have obtained a closed analytic expression for the vertex in the limit in which at least one of \q(1)(2)\ and \q(2)( 2)\ is large for arbitrary fixed values of the ratio q(1)(2)/q(2)(2). We compare our results with those obtained previously by Brodsky and L epage. It should be straightforward to test our predictions experiment ally.