Photoproduction of Λ(1405) on the Proton and Nuclei

The nature of Λ(1405) hyperon is still controversial as either an unstable K̄N bound state or L = 1 SU(3)-singlet three quark state coupled with the S-wave K̄N channels. Recent theoretical works predicted that the lineshape would be different for different charge combinations of the πΣ decay channels in the context of chiral dynamics plus final-state interaction. We have measured the lineshape of Λ(1405) for charged πΣ channels through p(γ, K⁺π)Σ reaction at 1.5-2,4 GeV. The observed lineshapes for π^-Σ^- and π⁺Σ^- channels turn out to be different, which implies that Λ(1405) could be interpreted as a bound-state of meson-baryon states.