Positive-parity excited baryons in a quark model with hyperfine interactions

Abstract

A quark model suggested by quantum chromodynamics with strong spin-dependent forces of magnetic-dipole-magnetic-dipole character perturbing a flavor-independent confinement potential is applied to lowlying positive-parity excited baryons. SU(3) is broken only by quark masses, and this leads to a new choice of basis states in the hyperon sector; couplings to $\overline{K}N$ are especially transparent in this basis. The results, which are largely determined by previous analyses, are in good agreement with the known properties of these states. Spin-orbit forces are once again found to be negligible.