Measurement of the p − p Elastic-Scattering Spin Parameter C LL at 11.75 GeV/ c for θ c . m . = 48 ° − 90 °

Results are presented of a measurement of the proton-proton elastic-scattering spin parameter ${C}_{\mathrm{LL}}=(L,L;0,0)$ at 11.75 GeV/c and ${\ensuremath{\theta}}_{\mathrm{c}.\mathrm{m}.}=48\ifmmode^\circ\else\textdegree\fi{}\ensuremath{-}90\ifmmode^\circ\else\textdegree\fi{}$. The value of ${C}_{\mathrm{LL}}$ is nearly constant and is approximately -0.16 in this angular region. This behavior is consistent with only one of the many models proposed describing the interaction via the hard scattering of two quarks.