Analysis of the new Crystal Ball data on $K^{-}p\to {\pi }^0\Lambda$ reaction with beam momenta of $514\sim 750$ MeV/$c$

Abstract

The Crystal Ball Collaboration has recently reported the differential cross sections and $\Lambda$ polarization for the reaction $K^{-}p\to {\pi }^0\Lambda$ 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 $\Sigma (1189)$, ${\Sigma }^{\ast }(1385)$, $\Sigma (1670){\frac{3}{2}}^{-}$, $\Sigma (1775){\frac{5}{2}}^{-}$, as well as a $\Sigma (1635){\frac{1}{2}}^{+}$, which is compatible with the 3-star $\Sigma (1660){\frac{1}{2}}^{+}$ in PDG, our results can well reproduce the experimental data. The parameters on the $\Sigma$ resonances and related couplings are studied.

Comments: Polarization data from the Crystal Ball Collaboration are included for the fit