A complete measurement of spin-observables for intermediate-energy inclusive quasielastic polarized proton scattering from C

The complete set of Wolfenstein parameters, the polarization, the asymmetry of scattering and the unpolarized double-differential cross section are presented for inclusive quasielastic proton scattering from ¹²C at a central momentum transfer of q = 1.9 fm⁻¹ and incident energies of 290 and 420 MeV. The spin observables D₀, D_x, D_y and D_z as well as the longitudinal-to-transverse ratio of spin-flip probabilities are extracted from the data. Across the quasielastic continuum, the experimental data is compared to the variations expected from a single-scattering Fermi-gas approximation using the free NN amplitudes. Medium effects are evident in the pronounced quenching of the polarization parameter relative to the free value.