High-P⊥2 p−pelastic scattering in pure initial spin states

Abstract

We measured the cross section for proton-proton elastic scattering at 11.75 GeV/c using the Zero Gradient Synchrotron 52% polarized proton beam and a 60% polarized proton target. We measured $\frac{d\sigma }{\mathrm{dt}\left(\mathrm{ij}\right)\mathrm{}}$ in the ↑↑, ↓↓, and ↑↓ initial spin states perpendicular to the scattering plane in the range $P_{\perp }^{}{}_{}{}^2=2.0-3.6\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. We found that the asymmetry parameter $A$ decreases smoothly with increasing $P_{\perp }^{}{}_{}{}^2$ in this range, and that the spin-spin correlation parameter $C_{\mathrm{nn}}$ may have a minimum near $P_{\perp }^{}{}_{}{}^2=3\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$.