Evidence of the non-strange partner of pentaquark from the elementary K^+Λ photoproduction

The existence of the $J^p=1/2^+$ narrow resonance predicted by the chiral soliton model has been investigated by utilizing the new kaon photoproduction data. For this purpose, we have constructed two phenomenological models, which are able to describe kaon photoproduction from threshold up to W=1730 MeV. By varying the resonance mass, width, and $K\Lambda$ branching ratio in this energy range we found that the most convincing mass of this resonance is 1650 MeV. Using this result we estimate the masses of other antidecuplet family members.