Cross Sections and Transverse Single-Spin Asymmetries in Forward Neutral-Pion Production from Proton Collisions ats=200GeV

Measurements of the production of forward high-energy ${\pi }^0$ mesons from transversely polarized proton collisions at $\sqrt{s}=200\mathrm{GeV}$ 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 $\sqrt{s}\le 20\mathrm{GeV}$. The analyzing power is in qualitative agreement with perturbative QCD model expectations. This is the first significant spin result seen for particles produced with $p_T>1\mathrm{GeV}/c$ at a polarized proton collider.