Instantons and the singlet-coupling in the chiral quark model
arXiv:hep-ph/9812428 · doi:10.1103/PhysRevD.59.097503
Abstract
Chiral quark model with a broken-U(3) flavor symmetry can be interpreted as the effective theory of the instanton-dominated non-perturbative QCD. This naturally suggests the possibility of a negative singlet/octet coupling ratio, which has been found, in a previous publication, to be compatible with the phenomenological description of the nucleon spin-flavor structure.
9 pages