A meson-baryon molecular interpretation for some $\Omega_c$ excited baryons

TL;DR

This paper proposes that certain narrow $ ext{Omega}_c$ resonances are meson-baryon molecules, using vector meson exchange interactions, and finds structures matching observed resonances, suggesting they are $1/2^-$ states.

Contribution

It introduces a meson-baryon molecular interpretation for $ ext{Omega}_c$ states using unitarized coupled-channel analysis, a novel approach for these resonances.

Findings

Identifies two structures matching observed $ ext{Omega}_c(3050)^0$ and $ ext{Omega}_c(3090)^0$

Suggests these resonances are $1/2^-$ meson-baryon molecules

Highlights the importance of experimental spin-parity determination

Abstract

We explore the possibility that some of the five narrow $\Omega_c$ resonances recently observed at LHCb could correspond to pentaquark states, structured as meson-baryon bound states or molecules. The interaction of the low-lying pseudoscalar mesons with the ground-state baryons in the charm $+1$, strangeness $-2$ and isospin 0 sector is built from t-channel vector meson exchange, using effective Lagrangians. The resulting s-wave coupled-channel unitarized amplitudes show the presence of two structures with similar masses and widths to those of the observed $\Omega_c(3050)^0$ and $\Omega_c(3090)^0$. The identification of these resonances with the meson-baryon bound states found in this work would also imply assigning the values $1/2^-$ for their spin-parity. An experimental determination of the spin-parity of the $\Omega_c(3090)^0$ would help in disentangling its structure, as the quark-based models predict its spin-parity to be either $3/2^-$ or $5/2^-$.