Quantum-chromodynamic predictions for longitudinal spin-spin asymmetry in inclusive direct photon production at largepT

We calculate the longitudinal spin-spin asymmetry $A_{\mathrm{LL}}$ in inclusive direct photon production $\mathrm{pp}\to \gamma X$ and $\overline{p}p\to \gamma X$ at $\sqrt{s}=53\mathrm{}$ GeV and $3\lesssim p_T\lesssim 10$ GeV/c using perturbative QCD. We examine the sensitivity of $A_{\mathrm{LL}}$ to the input gluon and sea quark distributions. The largest uncertainty is introduced by the unknown form of the polarized gluon distribution function. The scale violations tend to decrease the magnitude of $A_{\mathrm{LL}}$ in both reactions.