Spin Correlation forppElastic Scattering atθc.m.=π2in the Energy Region of Dibaryon Resonances

Precise measurements are reported of the spin-correlation parameter $A_{\mathrm{NN}}$ for 500-800 MeV $\mathrm{pp}$ elastic scattering at ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=\frac{\pi }{2}$. While not reproducing the large value of $A_{\mathrm{NN}}$ reported earlier at 697 MeV, the data show a pronounced maximum in the 90° triplet-to-singlet ratio near the location of the reported ${}_{}{}^3{}_{}{}^{}F_3^{}{}_{}{}^{}$ dibaryon resonance. In contradiction with an earlier report, structure is not found in the moduli of the singlet and triplet amplitudes.