Appropriate observables for investigating narrow resonances in kaon photoproduction off a proton.

The existence of non-strange partner of pentaquark, the J^p = 1/2⁺ narrow resonance, has been investigated by utilizing kaon photoproduction off a proton. It is found that the corresponding mass is 1650 MeV and the appropriate observables for investigating the existence of this resonance are the recoiled hyperon polarization, the beam-recoil double polarization Cx, and differential cross section at backward angles. Future kaon photoproduction experiments should focus on these observables. [ABSTRACT FROM AUTHOR]