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

TL;DR

This paper performs a partial wave analysis of the $K^-p\to\pi^0\Lambda$ reaction using recent Crystal Ball data, identifying properties of $\\Sigma$ resonances and reproducing experimental observations with an effective Lagrangian approach.

Contribution

It introduces a detailed partial wave analysis incorporating multiple $\\Sigma$ resonances to interpret recent experimental data on the $K^-p\to\pi^0\Lambda$ reaction.

Findings

Successful reproduction of experimental differential cross sections and polarization data.

Determination of resonance parameters and couplings for $\\Sigma$ states.

Identification of a $\\Sigma(1635)$ resonance compatible with known states.

Abstract

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.