Measurement of the differences in the total cross section for antiparallel and parallel longitudinal spins and a measurement of parity nonconservation with incident polarized protons and antiprotons at 200 GeV/c

The highest-energy measurement of ??L(pp) and the first ever measurement of ??L(p¯p), the differences between proton-proton and antiproton-proton total cross sections for pure longitudinal spin states, are described. Data were taken using 200-GeV/c polarized beams incident on a polarized-proton target. The results are measured to be ??L(pp)=-42±48(stat)±53(syst) ?b and ??L(p¯p)=-256±124(stat)±109(syst) ?b. Many tests of systematic effects were investigated and are described, and a comparison to theoretical predictions is also given. Measurements of parity nonconservation at 200 GeV/c in proton scattering and the first ever of antiproton scattering have also been derived from these data. The values are consistent with zero at the 10-5 level.