Feasibility study of the K+d → K0pp reaction for the Θ+ pentaquark

We investigate theoretically the K(0)p invariant mass spectrum of the K(+)d -> K(0)pp reaction and scrutinize how the signal of the Theta(+) pentaquark, if it exists, emerges in the K(0)p spectrum. The most prominent advantage of this reaction is that we can clearly assess whether the Theta(+) exists or not as a direct-formation production without significant backgrounds, in contrast to other reactions such as photoproduction and pi-induced productions. We show that while the impulse or single-step scattering process can cover the Theta(+) energy region with an initial kaon momentum k(lab) approximate to 0.40 GeV/c in the laboratory frame, the contributions from double-step processes may have a potential possibility to reach the Theta(+) energy region with a higher kaon momentum k(lab) similar to 1 GeV/c. Assuming that the full decay width of the Theta(+) is around 0.5 MeV, we predict that the magnitude of the peak corresponding to the Theta(+) is around a few hundred mu b to 1 mb with the momentum of the kaon beam k(lab) approximate to 0.40 GeV/c while it is around less than or similar to 1 mu b with k(lab) approximate to 0.85 GeV/c. Thus, the Theta(+) peak is more likely to be seen at k(lab) approximate to 0.40 GeV/c than at k(lab) approximate to 0.85 GeV/c.