Chiral SU(3) Bethe Salpeter Model: Extension to SU(6) and SU(8) Spin-Flavor Symmetries

TL;DR

This paper extends the SU(3) chiral meson-baryon model to SU(6) and SU(8) symmetries, incorporating vector mesons, and successfully describes various baryon resonances including charmed states within a Bethe-Salpeter framework.

Contribution

It introduces a consistent SU(6) and SU(8) extension of the chiral Lagrangian with vector mesons, applying the Bethe-Salpeter approach to charmless and charmed baryons.

Findings

Reproduces SU(3) WT results for negative parity baryon resonances.

Provides insights into heavier and d-wave negative parity states.

Describes features of Lambda_c(2595) and Lambda_c(2625) resonances.

Abstract

Consistent SU(6) and SU(8) spin-flavor extensions of the SU(3) flavor Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian are constructed, which incorporate vector meson degrees of freedom. In the charmless sector, the on-shell approximation to the Bethe-Salpeter (BS) approach successfully reproduces previous SU(3) WT results for the lowest-lying s--wave negative parity baryon resonances. It also provides some information on the dynamics of heavier ones and of the lightest d-wave negative parity resonances, as e.g. the Lambda(1520). For charmed baryons the scheme is consistent with heavy quark symmetry, and our preliminary results in the strangeness-less charm C=+1 sector describe the main features of the three-star J^P=1/2^- Lambda_c(2595) and J^P=3/2^- Lambda_c(2625) resonances. We also find a second broad J^P=1/2^- state close to the Lambda_c(2595)