Photoproduction of $\Theta^+$ and other pentaquark states

Abstract

We present constraints on the {\it relative} photoproduction cross sections of positive parity pentaquark states, $\Sigma_5$, $\Lambda_5$, and $N_5$, based on a minimum phenomenology gained in $\gamma N \to K \Theta^+$ and their baryon-meson couplings as in the work of Close and Dudek. The possibility of anomalous signals in $\gamma p \to K^0_S (\Theta^+;\Sigma_d^+)$ is discussed. We emphasise the importance of comparing $\gamma N \to K \Theta^+$ with "conventional" states such as $\gamma N \to K \Sigma(1660)$.