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

TL;DR

This paper extends the Weinberg compositeness condition to resonances and applies it to the $ ext{Lambda}(1520)$, showing it is mainly a meson-baryon dynamically generated state with minimal genuine components.

Contribution

It introduces a generalized method to quantify the meson-baryon content in resonances, applied here to the $ ext{Lambda}(1520)$.

Findings

$ ext{Lambda}(1520)$ is predominantly a meson-baryon dynamically generated state.

Only about 15% of the wave function consists of other genuine components.

The analysis supports the meson-baryon nature of the 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 $\pi\Sigma^*$, $K\Xi^*$ 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.