Incorporating final-state correlation effects, we have reinvestigated the ${\gamma }^1\mathrm{H}\to K^{+}\Lambda$ elementary process. Our model not only resolves the persisting trouble of the small $\mathrm{KN}\Lambda$ coupling constant, but also yields agreement with cross-section data at higher energies. Using our amplitudes, we calculate angular distributions for the reaction ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\gamma , K^{+}){}_{\Lambda }{}^{16}{}_{}{}^{}\mathrm{N}$. While the forward cross section increases with increasing energy, the total cross section is almost constant from $E_{\gamma }=1.2\mathrm{}$ through 2 GeV, suggesting that rather low photon energies hold promise for exploration of hypernuclear excitations.

• Received 14 November 1988

DOI:https://doi.org/10.1103/PhysRevC.39.741