Determining the Theta^+ quantum numbers through the K^+pto π^+K^+n reaction

We study the $K^+p\to \pi^+K^+n$ reaction with some kinematics suited to the production of the $\Theta^+$ resonance recently observed. We show that, independently of the quantum numbers of the $\Theta^+$, a resonance signal is always observed in the $K^+$ forward direction. In addition, we also show how a combined consideration of the strength at the peak, and the angular dependence of polarization observables can help determine the $\Theta^+$ quantum numbers using the present reaction.