Decays of Baryon Resonances into K Lambda, K^+ Sigma^0 and K^0 Sigma^+

TL;DR

This paper reports measurements of cross sections, asymmetries, and polarisations for specific gamma p reactions involving kaons and sigma hyperons, revealing evidence for new baryon resonances in the 1.6-2.3 GeV energy range.

Contribution

It presents a combined analysis of multiple photoproduction data sets, discovering new baryon resonances and providing detailed resonance parameters.

Findings

Identification of a new P_{11} resonance at 1840 MeV

Evidence for two D_{13} states at 1870 and 2170 MeV

High-statistics measurements across a broad energy range

Abstract

Cross sections, beam asymmetries, and recoil polarisations for the reactions gamma p to K^+ Lambda ; gamma to K^+ Sigma^0, and gamma p to K^0 Sigma^+ have been measured by the SAPHIR, CLAS, and LEPS collaborations with high statistics and good angular coverage for centre-of-mass energies between 1.6 and 2.3 GeV. The combined analysis of these data with data from pi and eta photoproduction reveals evidence for new baryon resonances in this energy region. A new P_{11} state with mass 1840 MeV and width 140 MeV was observed contributing to most of the fitted reactions. The data demand the presence of two D_{13} states at 1870 and 2170 MeV.