Proton-Proton Polarization Data: Possible Evidence for Exotic Peripheral Resonances?

We first draw attention to the important fact that proton-proton polarization is very similar to ${\pi }^{+}$-proton polarization for lab momenta 3 to 17.5 GeV/c. In particular, there is a double zero at $\mathrm{}\left|t\right|\mathrm{}\approx 0.8$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. This $\mathrm{pp}$ polarization structure is in disagreement with the expectations of simple Regge-pole schemes. We discuss briefly some modifications in these schemes, and suggest the possibility of peripheral resonances even in exotic channels. We also show how the observed $\mathrm{pp}$, $\pi p$, and $\mathrm{Kp}$ polarizations may be interpreted in terms of an optical model.