Lambda(1405) as a K-bar N Feshbach resonance in the Skyrme model

Abstract

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