Coupling ofK¯*Nto the Λ(1520)

Abstract

We study the coupling of the $\ensuremath{\Lambda}(1520)\ensuremath{\equiv}{\ensuremath{\Lambda}}^{*}$ resonance to the ${\overline{K}}^{*}$ vector meson and nucleon. This coupling is not directly measured from the resonance decay, but is expected to be important in hyperon production reactions, in particular for the exotic ${\ensuremath{\Theta}}^{+}$ production. We compute the coupling in two different schemes, one in the chiral unitary model where the ${\ensuremath{\Lambda}}^{*}$ is dominated by the quasibound state of mesons and baryons, and the other in the quark model where the resonance is a p-wave excitation in the three valence quarks. Although it is possible to construct both models such that they reproduce the $\overline{K}N$ and $\ensuremath{\pi}\ensuremath{\Sigma}$ decays, there is a significant difference between the ${\ensuremath{\Lambda}}^{*}{\overline{K}}^{*}N$ couplings in the two models. In the chiral unitary model $|{g}_{{\ensuremath{\Lambda}}^{*}{\overline{K}}^{*}N}|~1.5$, while in the quark model $|{g}_{{\ensuremath{\Lambda}}^{*}{\overline{K}}^{*}N}|~10$. The difference of the results stems from the different structure of the ${\ensuremath{\Lambda}}^{*}$ in both models, and hence, an experimental determination of this coupling would shed light on the nature of the resonance.