Semileptonic decays of charmed mesons in the effective action of QCD

Abstract.

Within the framework of phenomenological Lagrangians we construct the effective action of QCD relevant for the study of semileptonic decays of charmed mesons. Hence we evaluate the form factors of $D \rightarrow P(0^-) \ell^+ \nu_{\ell}$ at leading order in the 1/N _C expansion and, by demanding their QCD-ruled asymptotic behavior, we constrain the couplings of the Lagrangian. The features of the model-independent parameterization of form factors are provided, and their relevance for the analysis of experimental data are pointed out.