Study of K-p→Λπ+π-, Λπ0 and γN→K+Σ*

A new particle Σ* with J^P = 1/2^- was predicted by unquenched quark models with its mass around the well established Σ*(1385) with J^P = 3/2⁺. Here we re-examine some old data of the K^-p→Λπ⁺π^- reaction. We re-fit the data for kaon beam momenta in the range of 1.0-1.8 GeV and the energies around Λ(1520) peak. Both studies show evidence for the existence of Σ* with J^P = 1/2^- around 1380 MeV. And then we also study the recent data on Σ*(1385) production in the γn→K⁺πΛ reaction by the LEPS collaboration and the reaction K^-p→π⁰Λ by the Crystal Ball Collaboration. Our results not only indicate the possible existence of Σ(1380)1/2^-, but also firmly confirm the existence of Σ(1660)1/2⁺.