Electromagnetic Production of Kaons on the Nucleon

Kaon photo- and electroproduction in all six isospin channels are investigated by means of an isobaric model. It is found that existing models can only partially describe the current experimental data. Moreover, the extracted coupling constants are mostly inconsistent with the prediction of SU(3) symmetry or the information from hadronic reactions. In order to further analyze this problem, we introduce a form factor at the hadronic vertices $KNY$ (with $Y=\Lambda~ \textrm{or}~ \Sigma$) and study its behavior qualitatively. Our result suggests the need of more accurate experiments, especially in the charged $\Sigma$ and the neutral $K^0$ channels.