The role of vector-baryon channels and resonances in the γp→K0Σ+ and γn→K0Σ0 reactions near the K⁎Λ threshold

We have studied the γp→K0Σ+ reaction in the energy region around the K⁎Λ and K⁎Σ thresholds, where the CBELSA/TAPS cross section shows a sudden drop and the differential cross section experiences a transition from a forward-peaked distribution to a flat one. Our coupled-channel model incorporates the dynamics of the vector meson-baryon interaction which is obtained from the hidden gauge formalism. We find that the cross section in this energy region results from a delicate interference between amplitudes having K⁎Λ and K⁎Σ intermediate states. The sharp downfall is dictated by the presence of a nearby N⁎ resonance produced by our model, a feature that we have employed to predict its properties. We also show results for the complementary γn→K0Σ0 reaction, the measurement of which would test the mechanism proposed in this work.