Baryons in the SU(2) and SU(3) NJL model: A review of results

Abstract

The semibosonized Nambu - Jona-Lasinio model in its SU(2) and SU(3) versions with scalar and pseudoscalar couplings is applied on the chiral circle to baryons (chiral quark soliton approach). The parameters of the model are fixed in the meson sector reproducing tf π , m π and m K . The constituent mass is chosen to be 420 MeV and no further parameter is adjusted. The baryons arise as a soliton of N c valence quarks coupled to the polarized Dirac sea. The calculations include 1 N c - rotational corrections and for the strange mass treated perturbatively the value m s = 180 MeV is used. The following agreement with the experimental data is obtained: With less than 15% deviation from experiment we obtain 〈 r 2 〉 c p , μ p , μ n , gA = g A (3), σ πN , g A (8), G p E ( q 2), G p M ( q 2), G n M ( q 2), E2 M1 , Δ- N-splitting, mass splittings of octet and decuplet baryons, magnetic moments of hyperons, isospin splittings of the octet and the Gottfried sum rule. With 30% deviation and at the borderline of exp. errors appear the electric neutron form factor and the other spin quantities g A (8) and Δu, Δd and Δs. Predictions are made for scalar form factor, strange form factors and tensor charges.