Measurements of $C_{\mathrm{NN}}$ in Proton-Proton Scattering

The spin-spin correlation parameter $C_{\mathrm{NN}}$ for $p-p$ scattering has been measured at 5 energies between 305 and 415 MeV. Measurements were made over the angular range of 50° to 90° in the c.m. system. A polarized beam, produced by scattering of the internal proton beam of the Chicago cyclotron, and the Argonne polarized proton target were used for the experiment. Results obtained for $C_{\mathrm{NN}}\left(90\mathrm{}°\right)$ are: 0.52±0.08 at 305 MeV, 0.48±0.08 at 330 MeV, 0.50±0.05 at 358 MeV, 0.46±0.06 at 386 MeV, and 0.42±0.04 at 415 MeV. Comparisons with other experimental results and with theoretical and phenomenological models will be made.