The Constituent Chiral Quark Model revisited

We reconsider the Constituent Chiral Quark Model of Manohar and Georgi in the presence of SU(3)LxSU(3)R external sources. As recently emphasized by Weinberg, the corresponding effective Lagrangian is renormalizable in the large-Nc limit. We show, however, that the number of the required counterterms depends crucially on the value of gA and it is minimized for gA=1. We then find that with a rather small value for the constituent quark mass, which we fix phenomenologically to MQ=(190±40) MeV, the model reproduces rather well the values of several well-known low-energy constants. We also comment on the limitations of the model as well as on a few exceptional applications, to more complicated low-energy observables, where one can expect the model to make reasonably good predictions.