The s-wave charmed baryon resonances from a coupled-channel approach with heavy quark symmetry

TL;DR

This paper develops a coupled-channel model respecting heavy-quark symmetry to study charmed baryon resonances, extending previous SU(4) models to an SU(8) scheme, and identifies some states with experimental resonances.

Contribution

It introduces an SU(8) spin-flavor scheme for dynamically generating charmed baryon resonances, improving upon SU(4) models by better implementing flavor symmetry breaking.

Findings

Some resonances match observed baryon states.

Lambda_c(2595) shifts from ND to ND* dominance.

Model suggests new states requiring further data.

Abstract

We study charmed baryon resonances which are generated dynamically within a unitary meson-baryon coupled channel model that treats the heavy pseudoscalar and vector mesons on equal footing as required by heavy-quark symmetry. It is an extension of recent SU(4) models with t-channel vector meson exchanges to a SU(8) spin-flavor scheme, but differs considerably from the SU(4) approach in how the strong breaking of the flavor symmetry is implemented. Some of our dynamically generated states can be readily assigned to recently observed baryon resonances, while others do not have a straightforward identification and require the compilation of more data as well as an extension of the model to d-wave meson-baryon interactions and p-wave coupling in the neglected s- and u-channel diagrams. Of several novelties, we find that the Lambda_c(2595), which emerged as a ND quasi-bound state within the SU(4) approaches, becomes predominantly a ND* quasi-bound state in the present SU(8) scheme.