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

Abstract

Precise measurements are reported of the spin-correlation parameter ${A}_{\mathrm{NN}}$ for 500-800 MeV $\mathrm{pp}$ elastic scattering at ${\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}=\frac{\ensuremath{\pi}}{2}$. While not reproducing the large value of ${A}_{\mathrm{NN}}$ reported earlier at 697 MeV, the data show a pronounced maximum in the 90\ifmmode^\circ\else\textdegree\fi{} 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.