Photoproduction of η-mesons on the deuteron above S₁₁(1535) in the presence of a narrow P₁₁(1670)-resonance

Incoherent photoproduction of η -mesons on the deuteron is considered. The main attention is paid to the region above the S ₁₁(1535) -resonance where a rather narrow resonance-like structure in the total cross-section extracted for γn → ηn has been reported. The corresponding experimental results are analyzed from the phenomenological standpoint within the model containing a baryon P₁₁ with a mass of about 1670MeV and a width less than 30MeV. This resonance was suggested in some recent works as a nonstrange member of the pentaquark antidecuplet with J ^P = 1/2⁺ . The calculation is also performed for the polarized and unpolarized angular distributions of η -mesons. In addition, we present our predictions for the cross-sections of the neutral kaons and double pion photoproduction, where the same narrow P ₁₁(1670) -resonance is assumed to contribute through the decay into K ⁰Λ and πΔ configuration.