Quantum- chromodynamic predictions for inclusive spin-spin asymmetries at large transverse momentum

Abstract

We discuss predictions for the asymmetry ${A}_{\mathrm{LL}}$ in the inclusive production at large ${p}_{T}$ of charged and neutral pions by longitudinally polarized protons. We work in the framework of a hard-scattering model based on perturbative quantum chromodynamics. Various assumptions for the distribution of the proton's spin among its constituents---quarks, ocean antiquarks, and gluons---and the effects of scaling violations on the parton distributions are considered.