Low-energy QCD: Chiral coefficients and the quark-quark interaction

A detailed investigation of the low-energy chiral expansion is presented within a model truncation of QCD. The truncation allows for a phenomenological description of the quark-quark interaction in a framework which maintains the global symmetries of QCD and permits a 1/${\mathit{N}}_{\mathit{c}}$ expansion. The model dependence of the chiral coefficients is tested for several forms of the quark-quark interaction by varying the form of the running coupling, α(${\mathit{q}}^2$), in the infrared region. The pattern in the coefficients that arises at tree level is consistent with large ${\mathit{N}}_{\mathit{c}}$ QCD, and is related to the model truncation. © 1996 The American Physical Society.