Kaon photoproduction off proton

Dalibor Skoupil,Petr Bydžovský,A Wrońska,C Guaraldo,H Ströher,A Magiera

doi:10.1051/epjconf/201613005018

Abstract

We have recently constructed our version of the Regge-plus-resonance (RPR) model and two variants of an isobar model for photoproduction of kaons on the proton, utilizing new experimental data from CLAS, LEPS, and GRAAL collaborations for adjusting free parameters of the models. Higher-spin nucleon (3/2 and 5/2) and hyperon (3/2) resonances were included using the consistent formalism by Pascalutsa and found to play an important role in data description. The set of chosen nucleon resonances in our new isobar models agrees well with the set of the most probable contributing states determined in the Bayesian analysis with the RPR model whilst only 6 out of 10 N *’s selected in the RPR fit of ours overlap with the nucleon resonant states in the Bayesian analysis. Results of two versions of the isobar model are compared to the new version of the RPR model and experimental data in the third-resonance region and their properties are discussed. We place an emphasis on the choice of resonances, the predictions in the forward- and backward-angle region as well as the choice of the hadron form factor.

Highlights

Introduction and methodologyThe study of kaon-hyperon electro- and photoproduction from nucleons in the nucleon resonance region supplies important information about the spectrum of baryon resonances and interactions in hyperon-nucleon systems which arise from Quantum Chromodynamics
In the fitting procedure of isobar-model parameters, the CLAS data sets were limited in energy to W < 2.4 GeV and W < 2.2 GeV for differential cross section and hyperon polarization, respectively, whereas for the adjustment of RPR free parameters these data sets were used in their entirety
In comparison to the isobar model, we had less free parameters to optimize and more data available when we went through the fitting procedure of the RPR model

Summary

Introduction

We focus on single-channel isobar models and neglect all higher-order effects, e.g. rescattering or an interaction in the final state, assuming that their influence on results is included, to some extent, by means of effective values of the coupling constants fitted to experimental data. The hybrid Regge-plus-resonance (RPR) model, constructed by the Ghent group [6, 8], allows to describe the kaon-hyperon photo- and electroproduction from the threshold up to energies well above the resonance region (Eγ ≈ 16 GeV).

Results

Conclusion