In this work, we have obtained the decay fraction of the semileptonic B decays , where is a Pseudoescalar (Vector) meson and is the heavy lepton . Using the relativistic Quark Model of Wirbel-Stech-Bauer and the non-relativistic Quark model of Isgur-Scora Gristein-Wise), we have obtained the numerical values of the Branching ratios for these decays. Moreover, we establish a comparison between the predictions of these two models.
Keywords: semileptonic decays; B meson; quark models.