Spin Analyzing Power inp−pElastic Scattering at 28 GeV/c

The analyzing power, $A$, was measured in proton-proton elastic scattering with use of a polarized proton target and 28-GeV/c primary protons from the alternating-gradient synchrotron. Over the ${P_{\perp }}^2$ range of 0.5 to 2.8 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$, the data show interesting structure. There is a rather sharp dip at ${P_{\perp }}^2=0.8\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ corresponding to the break in the elastic differential cross section at the end of the diffraction peak.