Aspects of χ and ψ production in polarized proton-proton collisions

Several topics of relevance to low transverse momentum ψ and χ_1,2(c {Mathematical expression}) production in polarized proton-proton collisions are discussed. The leading O(α_S³) contributions to the low p_T χ₁ production cross-sections via gg, qg, and q {Mathematical expression} initial states are calculated as well as the corresponding spin-spin asymmetries. We find that χ₁ production increases relative to direct ψ and χ₂ production, providing up to 25% of the observable e^*e^- pairs arising from ψ decays in pp collisions at √s=500 GeV. The spin-dependence of χ₁ production, however, is much smaller than for either direct ψ or χ₂ production and so will likely be far less useful than either process in probing the polarized gluon structure function of the proton. A subset of the O(α_S³) radiative corrections to χ₂ production involving initial state quarks are also performed and compared to leading order gg→χ₂ predictions.