Recent Results in Semileptonic B Decays With BaBar

Abstract

In this note, recent results of studies of semileptonic B meson decays from \babar are discussed and preliminary results given. In particular, a recent measurement of $\mathcal{B}(B \to D^{(*)}\tau \nu)$ and the ratio $\mathcal{B}(B \to D^{(*)}\tau \nu)/\mathcal{B}(B \to D^{(*)}\ell \nu)$ is presented. For the $D^*$ mode, a branching fraction of $1.79\pm0.13\stat\pm0.17\syst$ is found, with a ratio of $0.325\pm0.023\stat\pm0.027\syst$. For the $D$ mode, the results are $1.04\pm0.12\stat\pm0.14\syst$ and $0.456\pm0.053\stat\pm0.056\syst$, respectively. In addition, a study of $B_s$ production and semileptonic decays using data collected in a center-of-mass energy region above the \Y4S resonance is discussed. The semileptonic branching fraction $\mathcal{B}(B_s \to \ell \nu X)$ is measured to be $9.9{}^{+2.6}_{-2.1}\stat{}^{+1.3}_{-2.0}\syst$.