HYPERON RESONANCES IN RADIATIVE KAON CAPTURE∗

We use crossing symmetry to extend our Regge model for electromag-netic kaon production from the proton to the case of radiative kaon capture. Our model is based on the exchange of the K(494) and K∗(892) Regge trajectories in the t-channel. We use the parameters fitted to describe the p(γ,K+)Y reaction to make predictions for the p(K−, γ)Y process. The differential crosss-sections of the latter for kaon momenta of 520 and 750 MeV/c show a satisfactory agreement with data from the Crystal Ball Collaboration. PACS numbers: 11.10.Ef, 11.55.Jy, 25.80.Nv Mapping out the properties (masses, coupling strengths, excitation ener-gies,...) of baryon resonances will tell us a great deal about the dynamics of QCD in the confinement region. Many resonance models, for example, predict a denser baryon spectrum than experimentally observed [1–4]. Par-ticularly interesting channels are those involving the production of a kaon (KΛ or KΣ) because they also allow access to the strangeness content of the baryons. Over the last years, we have developed a Regge-plus-resonance (RPR) model for kaon electro- and photoproduction from the nucleon [5–7]. The model can be extended straightforwardly to describe the radiative kaon cap-ture processes, using crossing symmetry. In the latter process, hyperon resonances can be excited. Therefore, the two different reactions offer an op-portunity of studying both the nucleon and the hyperon spectrum in a single framework. The RPR model provides the amplitude M(k, p; pY, pK) for the kaon production process. Here, k, p, pY and pK are the photon, proton, hyperon and kaon fourmomenta, respectively. The amplitude comprises a sum o