A meson-baryon molecular interpretation for some Ωc excited states

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 contribute to a better understanding of its structure, as the quark-based models predict its spin-parity to be either 3/2(-) or 5/2(-). Predictions for the analogue bottom Omega(-)(b) resonances are also given.