QCD analysis of $F_2^{\gamma}(x,Q^2)$: an unconventional view

Abstract

Elements of the alternative approach to hard collisions of photons, proposed recently by the author, are reviewed, with particular attention to QCD analysis of $F^{\gamma}_2$. This approach is based on clear separation of genuine QCD effects from those of pure QED origin and does not rely on the assumption that parton distribution functions of the photon behave as $\alpha/\alpha_s$. It differs significantly from the conventional one, as illustrated on the example of charm contribution to $F_{2}^{\gamma}$, recently measured at LEP.