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

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 $\frac{d\ensuremath{\sigma}}{\mathrm{dt}(\mathrm{ij})}$ in the \ensuremath{\uparrow}\ensuremath{\uparrow}, \ensuremath{\downarrow}\ensuremath{\downarrow}, and \ensuremath{\uparrow}\ensuremath{\downarrow} initial spin states perpendicular to the scattering plane in the range $P_{\ensuremath{\perp}}^{}{}_{}{}^{2}=2.0\ensuremath{-}3.6$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$. We found that the asymmetry parameter $A$ decreases smoothly with increasing $P_{\ensuremath{\perp}}^{}{}_{}{}^{2}$ in this range, and that the spin-spin correlation parameter ${C}_{\mathrm{nn}}$ may have a minimum near $P_{\ensuremath{\perp}}^{}{}_{}{}^{2}=3$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$.