QCD predictions for the spin dependent photonic structure functiong1γ(x,Q2)in the lowxregion of future linear colliders

Abstract

The spin dependent structure function ${g}_{1}^{\ensuremath{\gamma}}{(x,Q}^{2})$ of the polarized photon is analyzed within the formalism based upon the unintegrated spin dependent parton distributions incorporating the LO Altarelli-Parisi evolution and the double ${\mathrm{ln}}^{2}(1/x)$ resummation at low values of Bjorken parameter x. We analyze the effects of the double ${\mathrm{ln}}^{2}(1/x)$ resummation on the behavior of ${g}_{1}^{\ensuremath{\gamma}}{(x,Q}^{2})$ in the low x region which may be accessible in future linear ${e}^{+}{e}^{\ensuremath{-}}$ and $e\ensuremath{\gamma}$ colliders. The sensitivity of the predictions on the possible nonperturbative gluon content of the polarized photons is analyzed. Predictions for spin dependent gluon distribution $\ensuremath{\Delta}{g}^{\ensuremath{\gamma}}{(x,Q}^{2})$ are also given.