The composite nature of the $\Lambda (1520)$ resonance

Abstract

Recently, the Weinberg compositeness condition of a bound state was generalized to account for resonant states and higher partial waves. We apply this extension to the case of the $\Lambda (1520)$ resonance and quantify the weight of the meson-baryon components in contrast to other possible genuine building blocks. This resonance was theoretically obtained from a coupled channels analysis using the s-waves $\pi {\Sigma }^{\ast }$, $K{\Xi }^{\ast }$ and the d-waves $\bar{K}N$ and $\pi \Sigma$ channels applying the techniques of the chiral unitary approach. We obtain that this resonance is essentially dynamically generated from these meson-baryon channels, leaving room for only $15\%$ weight of other kind of components into its wave function.