Coupled-channel analysis of $K\Sigma$ production on the nucleon up to 2.0 GeV

TL;DR

This paper develops a coupled-channel effective Lagrangian model to analyze $K ext{Sigma}$ production on nucleons up to 2 GeV, incorporating recent experimental data to extract resonance properties and improve understanding of reaction mechanisms.

Contribution

It introduces a comprehensive coupled-channel approach that respects unitarity and gauge invariance, providing new insights into resonance couplings in $K ext{Sigma}$ production up to 2 GeV.

Findings

Resonances and background are both crucial for accurate angular and polarization data fit.

The model successfully reproduces experimental data with good quality.

Properties of isospin 3/2 resonances are detailed and discussed.

Abstract

A coupled-channel effective Lagrangian model respecting unitary and gauge invariance is applied to the combined analysis of the $(\pi,\gamma) N \to K\Sigma$ reactions for the center of mass energies up to 2 GeV. The recent photoproduction data obtained by the CLAS, CBELSA, LEPS, and GRAAL groups are included into our calculations with the aim to extract the resonance couplings to the $K\Sigma$ state. Both resonances and background contributions are found to be important to reproduce a correct shape of the angular distributions and polarization observables. Our description to the data is of good quality. The extracted properties of isospin $I = 3/2$ resonances are discussed in detail while the $I = 1/2$ resonances are largely determined by the non-strangeness channels.