On QCD analysis of stucture function $F_2^{\gamma}$ in alternative approach

TL;DR

This paper proposes an alternative QCD analysis method for the photon structure function $F_2^{}^{}$, highlighting differences from the conventional approach and their implications for future photon data analysis.

Contribution

It introduces a new approach to QCD analysis of $F_2^{}^{}$ that includes certain terms at lower orders and compares its numerical results with the standard method.

Findings

The alternative approach differs significantly from the conventional one at LO and NLO.

Numerical differences between the approaches are non-negligible for $F_2^{}^{}$.

The alternative method may impact future photon structure function analyses.

Abstract

The 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 conventional approach appear in higher orders. We show that this difference concerns also the photonic parton distribution functions. In the alternative approach, the complete LO analysis of $F_2^{\gamma}$ can be performed as all required quantities are known. At the NLO, however, one of the coefficient function is so far not available and thus only the photonic parton distribution function can be computed and compared to those of standard approach. We discuss the numerical difference of these approaches at the LO and the NLO approximation and show that in 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.