Effective $\boldsymbol{\bar{K}\!N}$ interaction with strong πΣ dynamics constrained by chiral SU(3) symmetry
We derive a single-channel effective $\bar{K}\!N$ interaction from chiral SU(3) coupled-channel dynamics, emphasizing the important role of the πΣ channel and the structure of the Λ(1405) resonance. The chiral low energy theorem requires strongly attractive interaction not only in the $\bar{K}\!N$ channel but also in the πΣ channel. As a consequence of the strong πΣ dynamics, the equivalent potential in single $\bar{K}\!N$ channel turns out to be less attractive than the one used in a purely phenomenological approach.