Weak decay form factors of heavy pseudoscalar mesons within a light-front constituent quark model

The transition form factors describing the semileptonic decays of heavy pseudoscalar mesons are investigated within a relativistic constituent quark model formulated on the light-front. For the first time the form factors are calculated in the whole accessible kinematical region, adopting meson wave functions derived from various effective qq interactions able to describe the meson mass spectra. It is shown that the decay rates of the B → Dℓνℓ, D → Kℓνℓ and D → πℓνℓ weak decays are mainly governed by the effects of the confinement scale, whereas the B → πℓνℓ decay rate is sensitive to the high-momentum components generated in the meson wave functions by the effective one-gluon-exchange interaction. Our results are consistent with available experimental data and predictions of lattice QCD calculations and QCD sum rules.