Relativistic description of exclusive semileptonic decays of heavy mesons

Using the quasipotential approach, we study exclusive semileptonic decays of heavy mesons taking into account relativistic effects. Because of a more complete relativistic description of the s quark, more precise expressions for semileptonic form factors are obtained. Various differential distributions in exclusive semileptonic decays of heavy mesons are calculated. It is argued that a consistent account of relativistic effects and a heavy quark effective theory motivated choice of the parameters of the quark-antiquark potential allow one to get a reliable value for the ratio A₂(0)/A₁(0) in the D-->K^*lν_l decay as well as the ratio Γ(D-->K^*lν_l)/Γ(D-->Klν_l). All calculated branching ratios are in accord with available experimental data.