Single-Spin Asymmetrics And Invariant Cross Sections Of The High Transverse-Momentum Inclusive Pi 0 Production In 200 Gev/C Pp And (P)Over-Barp Interactions

The pi(0) inclusive and semi-inclusive, single-spin asymmetries have been measured using transversely polarized, 200-GeV/c proton and antiproton beams colliding with an unpolarized hydrogen target. The measured asymmetries are consistent with zero within the experimental uncertainties for the kinematic region -0.153 GeV/c were not correct. These data indicate that PQCD expectations seem confirmed and the higher-twist contribution to the single-spin asymmetry in pi(0) production at x(F)=0 is not large. Additional evidence for such a conclusion comes from the measurement of a semi-inclusive pi(0) asymmetry, where associated charged particles are detected opposite to the pi(0) azimuthal direction. This experiment also provides high-statistics data on the inclusive pi(0) cross sections for pp and <(p)over bar p> collisions at root s approximate to 19.4 GeV.