Hard Exclusive Electroproduction of Pseudoscalar Mesons and QCD Axial Anomaly

Hard exclusive electroproduction of π0, η, η mesons by the longitudinal photons is considered. With the help of the QCD factorization theorem we show that at sufficiently large virtualities Q2 amplitudes of hard exclusive processes may be calculated in terms of the target parton distributions and the minimal Fock component of the pseudoscalar meson light cone wave function at zero interquark distances. This result justifies our calculation of the ratios of the π0 : η : η yields for the electroproduction processes off nucleons and deuterons based on the low energy QCD chiral dynamics, and the QCD E-mail address: [email protected], [email protected] E-mail address: [email protected] E-mail address: [email protected] On leave of absence from PSU.