Unpolarized and polarized elementary kaon electroproduction cross sections measured at MAMI

Present and future research into the electroproduction of kaons plays an important role at Mainz Microtron MAMI. With the KAOS spectrometer employed for kaon detection in the multi-spectrometer facility, cross section measurements of the exclusive p(e,e′K⁺)δ,Σ⁰ reactions at low momentum transfers have been performed. Isobar and Regge-plus-resonance models were compared with the data. These measurements have clearly discriminated between effective Lagrangian models for photo- and electroproduction of strangeness. New experiments with polarized beam at low four-momentum transfer are addressing the imaginary part of the longitudinal-transverse response in this process, that can be separated by flipping the beam electron helicity. These studies are important for the understanding of basic coupling constants in the isobar models and the electromagnetic form factors of the hadrons and their resonances involved in the process.