A Quark-Meson Model for Heavy Mesons: Semi-Leptonic Decays

I consider a model for heavy meson decays based on an effective quark-meson Lagrangian. The model is constrained by the known symmetries of QCD in the mQ → ∞ limit for the heavy quarks, and chiral symmetry in the light quark sector. Using a limited number of free parameters it is possible to compute several phenomenological quantities, e.g. the leptonic B and B∗∗ decay constants; the Isgur-Wise form factors: ξ, τ(3/2), τ(1/2), describing the semi-leptonic decays B → D(∗)lν, B → D∗∗lν; the form factors for heavy to light decays B → ρlν, B → a1lν. I show that the semileptonic heavy-to-light form factors calculated in the model fulfill the general relations that hold in QCD in the large energy limit for the final hadron. To appear in the Proceedings of the XXXIVth Rencontres de Moriond QCD and High Energy Hadronic Interactions Les Arcs 1800, France, March 20–27, 1999. HD-TVP-99-4 May 1998 A QUARK MODEL FOR HEAVY MESONS: SEMI-LEPTONIC DECAYS ALDO DEANDREA Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 19, D-69120 Heidelberg, Germany I consider a model for heavy meson decays based on an effective quark-meson Lagrangian. The model is constrained by the known symmetries of QCD in the mQ → ∞ limit for the heavy quarks, and chiral symmetry in the light quark sector. Using a limited number of free parameters it is possible to compute several phenomenological quantities, e.g. the leptonic B and B∗∗ decay constants; the Isgur-Wise form factors: ξ, τ (3/2), τ (1/2), describing the semi-leptonic decays B → Dlν, B → D∗∗lν; the form factors for heavy to light decays B → ρlν, B → a1lν. I show that the semileptonic heavy-to-light form factors calculated in the model fulfill the general relations that hold in QCD in the large energy limit for the final hadron.