Some aspects of Theta^+ parity determination in the reaction γ Nto 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.