Spin Dependence of High-p⊥Elastic Nucleon-Nucleon Scattering: Evidence for Quark Interchange?

High-$p_{\perp }$ elastic $\mathrm{NN}$ scattering is analyzed in terms of two quark-interchange amplitudes, which conserve and depend on quark helicities. Resulting relations between spin observables are compared with polarization data. Predictions are made for $\mathrm{np}$ scattering at $p_L=12\mathrm{}$ GeV/c, and for $\mathrm{pp}$ scattering at higher momenta, where the rise of ${A_{\mathrm{NN}}}^{\mathrm{pp}}$ (${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=90\mathrm{}°$) changes into a turn over. A sharp transition marks the onset of hard scattering.