Charmed and strange baryon resonances with heavy-quark spin symmetry

TL;DR

This paper models charmed and strange baryon resonances using a unitarized coupled-channel approach that incorporates heavy-quark spin symmetry, predicting new states and comparing them with experimental data.

Contribution

It extends the SU(3) Weinberg-Tomozawa chiral Lagrangian to SU(8) spin-flavor symmetry to dynamically generate baryon resonances with heavy-quark spin symmetry.

Findings

Resonances with negative parity from s-wave interactions are generated.

Some predicted states match experimental resonances, others suggest new states.

Identification of $ ext{Xi}_c(2790)$ and $ ext{Xi}_c(2815)$ as heavy-quark spin symmetry partners.

Abstract

We study charmed and strange baryon resonances that are generated dynamically by a unitary baryon-meson coupled-channel model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa chiral Lagrangian to SU(8) spin-flavor symmetry plus a suitable symmetry breaking. The model produces resonances with negative parity from s-wave interaction of pseudoscalar and vector mesons with $1/2^+$ and $3/2^+$ baryons. Resonances in all the isospin, spin, and strange sectors with one, two, and three charm units are studied. Our results are compared with experimental data from several facilities, such as the CLEO, Belle or BaBar Collaborations, as well as with other theoretical models. Some of our dynamically generated states can be readily assigned to resonances found experimentally, while others do not have a straightforward identification and require the compilation of more data and also a refinement of the model. In particular, we identify the $\Xi_c(2790)$ and $\Xi_c(2815)$ resonances as possible candidates for a heavy-quark spin symmetry doublet.