Transverse Polarization of $\Sigma^{+}(1189)$ in Photoproduction on a Hydrogen Target in CLAS

TL;DR

This paper reports the measurement of a large negative transverse polarization of the $\Sigma^+(1189)$ hyperon in photoproduction experiments, providing new data to test hyperon production models and search for missing baryon resonances.

Contribution

First measurement of $\Sigma^+(1189)$ transverse polarization in photoproduction on a hydrogen target using CLAS, offering crucial data to understand hyperon production mechanisms.

Findings

Observed up to 95% negative polarization

Data collected in photon energy range 1.0-3.5 GeV

Results aid in distinguishing hyperon production models

Abstract

Experimental results on the $\Sigma^+(1189)$ hyperon transverse polarization in photoproduction on a hydrogen target using the CLAS detector at Jefferson laboratory are presented. The $\Sigma^+(1189)$ was reconstructed in the exclusive reaction $\gamma+p\rightarrow K^{0}_{S} + \Sigma^+(1189)$ via the $\Sigma^{+} \to p \pi^{0}$ decay mode. The $K^{0}_S$ was reconstructed in the invariant mass of two oppositely charged pions with the $\pi^0$ identified in the missing mass of the detected $p\pi^+\pi^-$ final state. Experimental data were collected in the photon energy range $E_{\gamma}$ = 1.0-3.5 GeV ($\sqrt{s}$ range 1.66-2.73 GeV). We observe a large negative polarization of up to 95%. As the mechanism of transverse polarization of hyperons produced in unpolarized photoproduction experiments is still not well understood, these results will help to distinguish between different theoretical models on hyperon production and provide valuable information for the searches of missing baryon resonances.