Twist-3 effects for polarized virtual photon structure function $g_2^{\gamma }$

We investigate twist-3 effects in the polarized virtual photon. The structure function $g_2^{\gamma }$, which exists only for the virtual photon target and can be measured in future polarized $e^{+}{e}^{-}$ collider experiments, receives both twist-2 and twist-3 contributions. The twist-3 part is analyzed in pure QED interaction as well as in LO QCD. We find the twist-3 contribution is appreciable for the photon in contrast to the nucleon case.