The polarized photon structure function $g_1^\gamma(x,Q^2)$ in massive parton model in NLO

TL;DR

This paper calculates next-to-leading order corrections to the polarized photon structure function $g_1^rac{ ext{gamma}}$ in a massive parton model, revealing significant effects at high $x$ and confirming the sum rule.

Contribution

It introduces a detailed NLO calculation of $g_1^rac{ ext{gamma}}$ with massive quarks using advanced techniques, extending previous massless approximations.

Findings

NLO corrections are significant at large $x$.

The first moment sum rule of $g_1^rac{ ext{gamma}}$ holds up to NLO.

Coulomb singularity affects the behavior near quark pair production threshold.

Abstract

We investigate the one-gluon-exchange ($\alpha \alpha_s$) corrections to the polarized real photon structure function $g_1^\gamma(x,Q^2)$ in the massive parton model. We employ a technique based on the Cutkosky rules and the reduction of Feynman integrals to master integrals. The NLO contribution is noticeable at large $x$ and does not vanish at the threshold of the massive quark pair production due to the Coulomb singularity. It is found that the first moment sum rule of $g_1^\gamma$ is satisfied up to the NLO.