  This PhD thesis is a first step towards the control of the quantum
corrections in the Resonance Chiral Theory, the suggested framework to handle
QCD in the resonance region. After a theoretical introduction, Chapter 3 is
devoted to calculate the vector form factor of the pion at the next-to-leading
order in the 1/N(C) expansion. The ultraviolet behaviour of the calculation is
analyzed, together with the needed counterterms in the renormalization
procedure. The long-distance limit allows to determine the resonance
contribution to the low-energy constants of Chiral Perturbation Theory at the
NLO in 1/N(C). In Chapter 4 a study of the two-body hadronic form factors from
large-N(C) QCD is shown. We present a dispersive method which allows to
investigate the chiral LECs and we perform a NLO calculation of the scalar and
pseudoscalar two-point functions. Imposing the correct QCD short-distance
constraints, one determines their difference Pi(t)=Pi_S(t)-Pi_P(t) in terms of
the pion decay constant and resonance masses. Its low-momentum expansion fixes
then the ChPT coupling L(8). In Chapter 5 we evaluate the beta-function at
one-loop of the resonance lagrangian with one multiplet of scalar and
pseudoscalar resonances, up to bilinear couplings in the resonance fields, by
using the background field method.
