On the problem of D-meson leptonic and semileptonic decays

Abstract

The infinite mass effective theory, when a heavy quark mass goes to infinity, and chiral perturbation theory at the quark level, based on the extended Nambu-Jona-Lasinio model, are applied for the description of form factors of semileptonic decay D→ Ke +ν e and leptonic constant F D of D-mesons. The relation is derived connecting the form factor f +(0) with the ratio F D F π , which gives the estimate F D F π =1.21±0.17 . The slope parameter of the f + form factor is calculated in agreement with experimental data.