Spectrum of heavy baryons in the quark model

TL;DR

This paper investigates heavy baryons using a modified constituent quark model, analyzing their spectra and excitation modes across different quark mass regimes, from SU(3) symmetry to heavy quark symmetry.

Contribution

It introduces a quark model with mass-dependent color-Coulomb and antisymmetric LS terms, successfully reproducing observed heavy baryon masses and elucidating their excitation modes.

Findings

Model reproduces observed charmed and bottomed baryon masses.

Spectra evolve from SU(3) symmetry to heavy quark symmetry with increasing quark mass.

Negative-parity states show specific excitation modes related to quark mass differences.

Abstract

Single- and double- heavy baryons are studied in the constituent quark model. The model Hamiltonian is chosen as a standard one with two exceptions : (1) The color-Coulomb term depend on quark masses, and (2) an antisymmetric $LS$ force is introduced. Model parameters are fixed by the strange baryon spectra, $\Lambda$ and $\Sigma$ baryons. The masses of the observed charmed and bottomed baryons are, then, fairly well reproduced. Our focus is on the low-lying negative-parity states, in which the heavy baryons show specific excitation modes reflecting the mass differences of heavy and light quarks. By changing quark masses from the SU(3) limit to the strange quark mass, further to the charm and bottom quark masses, we demonstrate that the spectra change from the SU(3) symmetry patterns to the heavy quark symmetry ones.