Photo-excitation of hyperons and exotic baryon in gamma N --> K Anti-K N

Abstract

We investigate the reaction of $\gamma N \to K \bar{K} N$ focusing on the photoproduction of $\Lambda(1520)$ and putative exotic $\Theta(1540)$. We consider various background production mechanisms including the production of vector mesons, tensor mesons, and other $\Lambda$ and $\Sigma$ hyperons. We discuss the angular distribution of $\Lambda(1520)$ photoproduction cross section and the radiative decays of $\Lambda(1520)$. We also discuss what we expect for the invariant mass distributions if the $\Theta(1540)$ is formed in the reaction, with the parameters studied so far. We find that the peak in the $KN$ invariant mass distribution, if confirmed, can hardly come from the kinematic reflections, especially, due to the tensor meson backgrounds.