m_π and N_c dependence of rho and σ mesons from unitarized chiral perturbation theory

Abstract

We review the N_c and m_π dependence of the rho(770) and σ (or f_0(600) resonances generated with the Inverse Amplitude Method. The σ N_c behavior is at odds with being dominantly a q̅q̅ state, but there is a hint of a subdominant q̅q̅o component with a mass above 1 GeV. We find fair agreement with lattice results for the chiral extrapolation of the ρ mass, and that the ρ π π coupling is almost m_π independent whereas the σ π π depends strongly on m_π.