Polarization observable measurements for $\gamma p \to K^{+}\Lambda$ and $\gamma p \to K^{+}\Sigma^{0}$ for energies up to 1.5 GeV
Résumé
Beam asymmetries and hyperon recoil polarizations for the reactions $\gamma p \to K^{+}\Lambda$ and $\gamma p \to K^{+}\Sigma^{0}$ have been measured from the threshold production to 1500 MeV with the GRAAL facility located at the ESRF in Grenoble. These results complement the database for the beam asymmetry, covering for the first time the production threshold region. Recent theoretical analyses are presented for which the beam asymmetry data bring interesting new information and allow to better determine some resonance parameters. Most importantly, these results strengthen the need of a new D$_{13}$ state around 1900 MeV.