Measurement of polarisation observables in $K^0_s\Sigma^+$ photoproduction off the proton

TL;DR

This study measures polarization observables in the photoproduction of $K^0_s\,\Sigma^+$ off protons, providing new data on beam asymmetries and hyperon polarization that inform partial wave analyses and understanding of threshold phenomena.

Contribution

First measurement of photon beam asymmetries and recoil hyperon polarization in $\gamma p \rightarrow K^0_S\Sigma^+$ reaction up to 2250 MeV, offering new insights into hyperon photoproduction.

Findings

Photon beam asymmetries measured up to 2250 MeV.

Recoil hyperon polarization determined up to 1650 MeV.

Data compared to partial wave analyses and relevant for cusp-like structure interpretation.

Abstract

The reaction $\gamma \, p \rightarrow K^0_S\,\Sigma^+$ is studied in the photon energy range from threshold. Linearly polarised photon beams from coherent bremsstrahlung enabled the first measurement of photon beam asymmetries in this reaction up to $E_\gamma = 2250$ MeV. In addition, the recoil hyperon polarisation was determined through the asymmetry in the weak decay $\Sigma^+ \rightarrow p \pi^0$ up to $E_\gamma = 1650$ MeV. The data are compared to partial wave analyses, and the possible impact on the interpretation of a recently observed cusp-like structure near the $K^*$ thresholds is discussed.