Measurements ofCNNin Proton-Proton Scattering from 305 to 415 MeV

The spin-spin correlation parameter $C_{\mathrm{NN}}$ for $p-p$ scattering has been measured at four 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 for $C_{\mathrm{NN}}$ (90°) are compared with other experiments. The total set of experimental data indicates a strong energy dependence for $C_{\mathrm{NN}}$ (90°) with a minimum at approximately 500 MeV. A brief qualitative discussion of the behavior of $C_{\mathrm{NN}}$ (90°) is given.