Resonance Model forγ+N→Y+K

Abstract

A model which includes a resonance proposed by Kanazawa is used to describe the low-energy behavior of the reaction $\gamma +N\to K+{\Lambda }^0$. Only those contributions from the $N$, $K$, $K^{*}$, and $p_{\frac{1}{2}}$ nucleon resonance of Kanazawa are considered. The resonance is centered at 1718 MeV with a full width of 120 MeV. The parameters in the model are the coupling constants at the $N-{\Lambda }^0-K$ and $N-{\Lambda }^0-K^{*}$ vertices, the form factors at the $\gamma -K-K^{*}$ vertex, and the height of the resonance. These parameters are evaluated by fitting the Cornell differential cross-section data for the process $\gamma +p\to {\Lambda }^0+K^{+}$. The use of these parameters does not yield results in agreement with the one measured value of polarization of the ${\Lambda }^0$.