Rho meson properties

We study the mass, width and couplings of the lightest vector multiplet. Effective field theories based on chiral symmetry and a 1/N-C counting are adopted in order to describe the vector form factor associated to the two-pseudoscalar matrix element of the QCD vector current. The bare poles of the intermediate s-channel resonances are regularised through a Dyson-Schwinger-like summation. This procedure provides many interesting properties, as the pole mass M-rho(pole) = 764.1 +/- 2.7(-2.5)(+4.0) MeV and the chiral coupling L-9(r)(muo) = (7.04 +/- 0.05(-0.27)(+0.19)) (.) 10(-3), at mu(0) = 770 MeV. We show how the running affects the resonance parameters and that mu is really unphysical, so saturation occurs at any scale. This talk is mainly based on Ref. [1].