1304.7975 (A. Ramos et al.)

The role of vector-baryon channels and resonances in the $γp \to
K^0 Σ^+$ and $γn \to K^0 Σ^0$ reactions near the $K^*
Λ$ threshold    [PDF]

A. Ramos, E. Oset

We have studied the $\gamma p \to K^0 \Sigma^+$ reaction in the energy region around the $K^* \Lambda$ and $K^* \Sigma$ 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 argue that the downfall of the cross section in this energy region is a consequence of a delicate interference between amplitudes having $K^* \Lambda$ and $K^*\Sigma$ intermediate states. The location of the structure is sensitive to that 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 $\gamma n \to K^0 \Sigma^0$ reaction, the measurement of which would test the mechanism proposed here.

View original: http://arxiv.org/abs/1304.7975