Eur. Phys. J. C 22, 439-450 (2001)
DOI: 10.1007/s100520100830

The annihilation of virtual photons into pseudoscalar mesons

M. Diehl¹, P. Kroll² and C. Vogt<sup>2

1</sup>  Deutsches Elektronen-Synchroton DESY, 22603 Hamburg, Germany
²  Fachbereich Physik, Universität Wuppertal, 42097 Wuppertal, Germany

(Received: 30 August 2001 / Published online: 23 November 2001 - © Springer-Verlag / Società Italiana di Fisica 2001 )

Abstract
We investigate the possibility to constrain the pion distribution amplitude from the transition. For a surprisingly large range in the two photon virtualities we find that the transition form factor is essentially independent of the distribution amplitude. This in turn entails a parameter-free prediction of QCD. The form factors are also briefly discussed. We estimate that experimental studies might be feasible at the existing e⁺e^- experiments BaBar, Belle, and CLEO.

© Società Italiana di Fisica, Springer-Verlag 2001