Pseudovector versus pseudoscalar theory in kaon photoproduction from nucleons and nuclei

The reaction $^{1}\mathrm{H}$(\ensuremath{\gamma},${\mathrm{K}}^{+}$)${\mathrm{\ensuremath{\Lambda}}}^{0}$ is used to compare pseudovector with pseudoscalar coupling for the K\ensuremath{\Lambda}N vertex. The operator is based on diagrammatic techniques and includes the Born terms along with the ${\mathrm{K}}^{\mathrm{*}}$ and \ensuremath{\Sigma} exchange terms. Obtaining the coupling constants from a least squares fit shows that the data do not prefer one coupling over the other. Implanting the process into the nucleus yields only small differences between the two interactions.