The Λ⁎N interaction and two-body bound state based on chiral dynamics

The interaction of Λ⁎=Λ(1405) with a nucleon is studied from the viewpoint of chiral dynamics. We construct the coordinate space Λ⁎N potential in the meson-exchange picture, which serves as a fundamental ingredient for the study of the few-body nuclear systems with a Λ⁎, the Λ⁎-hypernuclei. The coupling constants concerning Λ⁎ are determined based on the chiral unitary model picture for the meson–baryon scattering where Λ⁎ is described as a superposition of two resonance poles. Solving the coupled-channel two-body Λ⁎N system, we find the higher energy Λ⁎N state develops an s-wave quasi-bound state slightly below the threshold in the total spin S=0 channel, which acquires a finite width through the coupling to the lower energy Λ⁎N channel. We show important roles of the exchange contribution to the Λ⁎N potential.