Some aspects of $\Theta^+$ parity determination in the reaction $\gamma   N\to \Theta^+ \bar{K}\to N K \bar{K}$
  We analyze the problem of how to determine the parity of the $\Theta^+$ pentaquark in the reaction $\gamma N\to K\Theta\to NK\bar{K}$, where $N=n,p$. Our model calculations indicate that the contribution of the non-resonant background of the reaction $\gamma N\to NK\bar{K}$ cannot be neglected, and that suggestions to determine the parity based solely on the initial-stage process $\gamma N\to K\Theta$ cannot be implemented cleanly. We discuss the various mechanisms that contribute to the background, and we identify some spin observables which are sensitive. 
A.I. Titov, H. Ejiri, H. Haberzettl, and K. Nakayama