On the nature of the lightest scalar resonances

We briefly review the recent progresses in the new unitarization approach being developed by us. Especially we discuss the large N-c pi pi scatterings by making use of the partial wave S matrix parametrization form. We find that the a pole may move to the negative real axis on the second sheet of the complex s plane, therefore it raises the interesting question that this 'sigma' pole may be related to the sigma in the linear sigma model.Physics, NuclearCPCI-S(ISTP)