Single-spin asymmetries and invariant cross sections of the high transverse-momentum inclusive pi0 production in 200 GeV/c proton-proton and antiproton-proton interactions

The ?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 a value of zero within the error bars for the kinematic regions, -0.15<xF<+0.15 and 1<pT<4.5 GeV/c. These data indicate that the higher-twist contribution in QCD to the single-spin asymmetry in inclusive ?0 production may not be as large as was previously expected. Additional evidence for such a conclusion comes from the measurement of a semi-inclusive ?0-charged particle asymmetry, where the associated charged particles are detected opposite to the ?0 azimuthal direction. This experiment also has a high-statistics measurement of the inclusive ?0 cross sections for pp and mathp collisions at 200