Spin structure function of the virtual photon

TL;DR

This paper explores the spin structure of virtual photons in QCD beyond leading order, revealing that the first moment of the spin structure function is non-zero, unlike the real photon case, supported by numerical analysis.

Contribution

It provides the first detailed analysis of the virtual photon spin structure function beyond leading order in QCD, highlighting its non-vanishing first moment.

Findings

First moment of $g_1^(x,Q^2,P^2)$ is non-zero for virtual photons.

Numerical results support the theoretical prediction.

Contrasts with the real photon case where the first moment vanishes.

Abstract

We investigate the spin structure of the virtual photon beyond the leading order in QCD. The first moment of the virtual photon spin structure function $g_1^\gamma(x,Q^2,P^2)$ with QCD effects turns out to be non-vanishing in contrast to the real photon case. Numerical analysis for virtual as well as real photon case is presented.