Polarization in Proton-Proton Scattering at 130, 170, and 210 Mev

Using a 90% polarized proton beam, we have measured the polarization in $p-p$ scattering at center-of-mass angles between 20 and 81 degrees at 130 Mev, between 31 and 82 degrees at 170 Mev, and between 14 and 112 degrees at 210 Mev. The first two of these measurements are consistent with data previously published; the third involves an energy in the neighborhood of which earlier detailed work has not been done. The measurements are fitted by functions of the form $P\left(\theta \right)\sigma \left(\theta \right)=sin\theta cos\theta \Sigma \stackrel{K}{n=0\mathrm{}}{b}_{2n}{cos}^{2n}\theta , \mathrm{where} K=0, 1, or 2.$ At 210 Mev, a three-parameter least-squares fit yields $b_0=(2.78\mathrm{}\pm 0.16)$ mb/sterad, $b_2=(-2.24\mathrm{}\pm 0.17)$ mb/sterad, and $b_4=(2.96\mathrm{}\pm 0.77)$ mb/sterad. Statistical analysis of the data at 210 Mev indicates that $F$-wave effects, and in particular a nonvanishing $b_4$, are required for description of the scattering.