Measurement of the polarization elastic scattering in pure initial spin states at 11.75 GeV/c

The elastic differential cross section for proton proton scattering at 11.75 GeV/c was measured for the ↑↑, ↓↓, and ↑↓ initial spin states perpendicular to the scattering plane in the range of p2⊥=0.6→2.2 (GeV/c)2. The experiment was performed at the Argonne ZGS using a 50% polarized beam and a 65% polarized target. We confirmed that the asymmetry parameter, A, decreases with energy in the diffraction peak, but is approximately energy—parameter CPinn acquires rather dramatic structure, and at large p2⊥ seems to grow with energy.