Progress and Issues in the Electromagnetic Production of Kaon on the Nucleon

Compared to the case of pions the electromagnetic productions of kaons are less understood. This is due to the fact that the strangeness quantum number is explicitly present in the final state of the process. Although the reactions involving kaons are slightly more complicated, the additional degrees of freedom created by the strangeness can give information not available from nucleons and pions. For instance, due to the conservation of the strangeness, the production of kaons is always accompanied by the creation of hyperons, which can be used to deeply explore the structure of the nucleus since they are not blocked by the Pauli principle. On the other hand, this elementary process provides an important input for the calculation of hypernuleus photoor electroproduction. Along with the fact that some N resonances that were predicted in quark models have only noticeable branching ratios into the KΛ channel, kaon photoand electroproduction clearly have drawn many attentions for more than five decades.