Analysis of the new Crystal Ball data on K^-ptoπ⁰Λ reaction with beam momenta of 514sim 750 MeV/c

The Crystal Ball Collaboration has recently reported the differential cross sections and $\Lambda$ polarization for the reaction $K^-p\rightarrow \pi^0\Lambda$ using an incident $K^-$ beam with momenta between 514 and 750 MeV/$c$. We make a partial wave analysis for this process with an effective Lagrangian approach and study the properties of some $\Sigma$ resonances around this energy range. With the inclusion of the 4-star resonances $\Sigma(1189)$, $\Sigma^*(1385)$, $\Sigma(1670){3\over 2}^-$, $\Sigma(1775){5\over 2}^-$, as well as a $\Sigma(1635){1\over 2}^+$, which is compatible with the 3-star $\Sigma(1660){1\over 2}^+$ in PDG, our results can well reproduce the experimental data. The parameters on the $\Sigma$ resonances and related couplings are studied.