Quark model for baryons based on quantum chromodynamics

Abstract

SU(3) flux-tube dynamics and asymptotic freedom are incorporated into a semirelativistic quark model of baryons and mesons. Good agreement with the energy levels of spin-averaged multiplets of mesons and baryons is obtained using conventional values for the strong-interaction coupling constant ${\alpha }_s$, the string tension $\sqrt{\sigma }$, and the constituent quark mass $m$. We calculate meson energy levels with angular momentum $L=0, 1, 2, 3, \mathrm{and} 4$ and baryon levels with $L=0, 1, \mathrm{and} 2$ to within 3% of their experimental values. Baryon radial excitations are also considered and the Roper resonance is calculated with ∼5% error. The three-body wave equation for the baryons is solved approximately using variational Monte Carlo methods which have been developed previously for nuclear-physics problems.