QCD analysis of the structure function F2γ in an alternative approach

An alternative approach to QCD analysis of the photon structure function F-2(gamma). is presented. It differs from the conventional one by the presence of the terms which, in a conventional approach, appear in higher orders. We show that this difference also concerns the photonic parton distribution functions. In the alternative approach, a complete leading order (LO) analysis of F-2(gamma) can be performed as all required quantities are known. At the next-to-leading order (NLO), however, one of the coefficient functions is so far not available and thus only the photonic parton distribution function can be computed and compared to that of the standard approach. We discuss the numerical difference of these approaches at the LO and the NLO approximations and show that in the case of F-2(gamma), this difference is non-negligible and may play an important role in the analysis on photon data of the future experiments.