Drell-Yan Non-Singlet Spin Cross Sections and Spin Asymmetry to $O({\alpha }_s^2)$ (II)

We present predictions for the non-singlet Drell-Yan longitudinal spin cross sections and spin asymmetry, $A_{LL}$, in proton-proton collisions at large $p_T$ at the RHIC energy of $200\text{gev}$ at next-to-leading order QCD. The higher order corrections to the non-singlet polarized cross section, ${\sigma }_{NS}^{LL}$, are sizeable and similar to those found for the unpolarized cross section. The non-singlet asymmetry parameter, $A_{LL}^{NS}$, is very stable against higher order corrections and is a direct measurement of the non-singlet (i.e. valence) polarized quark distributions within the proton.