Two-photon form factors of the pi0, eta and eta-prime mesons in the   chiral theory with resonances
  We have developed a phenomenological approach which describes very well the pi0, eta and eta-prime meson production in the two-photon interactions. The simultaneous description of the pi0, eta and eta-prime meson two-photon form factors is consistent with data in the space-like region. The obtained form factors are implemented in the event generator EKHARA and the simulated cross sections are presented. Uncertainties in the measured form factors coming from the model dependence in Monte Carlo simulations are studied. The model predictions for the form factor slopes at the origin are given and the high-Q2 limit is also discussed. 
Henryk Czyz, Sergiy Ivashyn, Alexandr Korchin, Olga Shekhovtsova
hep-ph hep-ex