Measurements of the Polarization ParametersPandCnninppElastic Scattering between 500 and 1200 MeV

Abstract

The polarization parameter $P$ and the spin correlation parameter $C_{\mathrm{nn}}$ in proton-proton elastic scattering have been measured in an experiment with a polarized-proton target in the beam extracted from the synchrotron "Saturne." The angular distribution of $P$ was measured at 7 energies between 0.5 and 1.2 GeV. The value of $P$ shows a maximum of +0.6 at about 700 MeV for a scattering angle of 45° in the center-of-mass system. At 1.2 GeV the value of $P$ is consistent with 0 for scattering angles ≳70° (momentum transfers $-t\gtrsim 0.8$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$]. The spin correlation coefficient $C_{\mathrm{nn}}$ was measured at three energies, 0.735, 0.978, and 1.19 GeV, by scattering a polarized-proton beam on the polarized target. The value of $C_{\mathrm{nn}}$ at 90° c.m. decreases from 0.7 to 0.4 as the energy increases from 0.735 to 1.19 GeV.