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 this resonance are the recoiled hyperon polarization, the beam-recoil double polarization C_x, and differential cross section at backward angles. Future kaon photoproduction experiments at low energies should focus on these observables. 
T. Mart
hep-ph nucl-th