We study kaon-nucleon systems in the Skyrme model in a method based on the bound state approach of Callan-Klebanov but with the kaon around the physical nucleon of the rotating hedgehog.This corresponds to the variation after projection, reversing the order of semiclassical quantization of 1/N c expansion. The method, however, is considered to be suited to the study of weakly interacting kaon-nucleon systems including looselyKN bound states such as Λ(1405). We have found a bound state with binding energy of order ten MeV, consistent with the observed state. We also discuss theKN interaction and find that it consists of an attraction in the middle range and a repulsion in the short range.

We study the (anti)kaon nucleon interaction in the Skyrme model. The kaon field is introduced as a fluctuation around the rotating Skyrmion for the nucleon. As an extension of our previous work, we study scattering states and examine phase shifts in various kaon-nucleon channels. Then we study the interaction, where we find that it consists of central and spin-orbit components for isospin channels, I = 0, 1, with energy dependence and nonlocality. The interaction is then fitted to a Shrödinger equivalent local potential for s-and p-waves.

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We describe the Λ(1405) hyperon as a Feshbach resonance of aKN quasi-bound state coupled by a decaying channel of πΣ in the Skyrme model. A weakly boundKN state is generated in the laboratory frame, while the Σ hyperon as a strongly bound state ofKN in the intrinsic frame.We obtain a coupling ofKN and πΣ channels by computing a baryon matrix element of the axial current. This coupling enables the decay of theKN bound state to πΣ. It is shown that the Skyrme model supports the Λ(1405) as a narrow Feshbach resonance.

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