We measured the angular dependence of the three recoil proton polarization
components in two-body photodisintegration of the deuteron at a photon energy
of 2 GeV. These new data provide a benchmark for calculations based on quantum
chromodynamics. Two of the five existing models have made predictions of
polarization observables. Both explain the longitudinal polarization transfer
satisfactorily.. Transverse polarizations are not well described, but suggest
isovector dominance.
