Cross Sections and Transverse Single-Spin Asymmetries in Forward Neutral-Pion Production from Proton Collisions at s~(1/2) = 200 GeV

摘要

Measurements of the production of forward high-energy π~0 mesons from transversely polarized proton collisions at s~(1/2) = 200 GeV are reported The cross section is generally consistent with next-to-leading order perturbative QCD calculations. The analyzing power is small at x_F below about 0.3, and becomes positive and large at higher x_F, similar to the trend in data at s~(1/2) ≤ 20 GeV. The analyzing power is in qualitative agreement with perturbative QCD model expectations. This is the first significant spin result seen for particles produced with p_T > 1 GeV/c at a polarized proton collider.