Multiple polarization observables must be measured to access the amplitude structure of pseudoscalar meson photoproduction off the proton. The hyperon-producing reactions are especially attractive to study, since the weak decays allow straightforward measurement of the induced and recoil polarization observables. In this paper we emphasize γ + p → K+ + Λ , discussing recent measurements of Cx, Cz, and P for this reaction. An empirical constraint on the helicity amplitudes is obtained. A simplified model involving spin-flip and spin-non-flip amplitudes is presented. Finally, a semi-classical model of how the polarization may arise is presented.
25.20.Lj Photoproduction reactions13.40.-f Electromagnetic processes and properties13.60.Le Meson production13.60.-r Photon and charged-lepton interactions with hadrons