  We study the resonance properties within chiral perturbation theory by
explicitly taking into account the U_A(1) anomaly effect. This assures we have
the appropriate degrees of freedom of low energy QCD in the large Nc limit. We
calculate the various resonance properties, such as mass, width and residues,
for the physical case, i.e. Nc=3. Then we extrapolate the values of Nc to study
the trajectories of resonance poles.
