Hyperfine splitting in a realistic basis for baryons

We calculate the positive and negative parity spectrum of baryons by diagonalizing the hyperfine Hamiltonian in a space corresponding to the SU(6) multiplets 56,70 and 20. THe highest spin considered is J = 7/2 for positive parity and J = 5/2 for negative parity. The main difference with the work of Isgur and Karl based on the harmonic oscillator is that we consider the more realistic unperturbed wave functions derived variationally by Carlson, Kogut and Pandharipande in a flux-tube quark model. The finite size of the quark is also taken into account.