Relativistic Description of Exclusive Semileptonic Decays of Heavy Mesons

Abstract

Using quasipotential approach, we have studied exclusive semileptonic decays of heavy mesons with the account of relativistic effects. Due to 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 consistent account of relativistic effects and HQET motivated choice of the parameters of quark-antiquark potential allow to get reliable value for the ratio $A_2(0)/A_1(0)$ in the $D\to K^*lν_l$ decay as well as the ratio~$Γ(D\to K^*lν_l)/Γ(D\to Klν_l)$. All calculated branching ratios are in accord with available experimental data.