First Measurement of the Branching Fraction of e^+e^- --> B0B0bar

We report the first measurement of the absolute branching fraction e^+e^- --> B0B0bar at the Upsilon(4S) resonance using data collected with the BABAR detector at the PEP-II asymmetric-energy e^+e^- storage ring. The analysis is performed with partial reconstruction of the decay B0bar --> D^{*+}\ell^{-} \bar{\nu}_{\ell}$, where the presence of a signal decay is determined using only the lepton and the soft pion from the D^{*} decay. By reconstructing events with one or two signal decays we obtain a preliminary result of e^+e^- --> B0B0bar = 0.486 \pm 0.010(stat.) \pm 0.009(sys.)$. Our result does not depend on branching fractions of the B0bar and the D^{*+} decay chains, on the individual simulated reconstruction efficiencies, on the ratio of the charged and neutral B meson lifetimes, or on the assumption of isospin symmetry.Comment: Latex, 5 pages, 2 figures, proceedings to the DPF 2004, 26 August-31 August 2004, Riverside, CA, US

Search For New Physics at BABAR

Using a full BABAR data sample of 426 $fb^{-1}$, we present improved measurements of the ratio ${\cal{R}}(D^{(*)}) = {\cal{B}} (\bar{B} \to D^{(*)}\tau^{-}\bar{\nu}_{\tau})/$ ${\cal{B}} (\bar{B} \to D^{(*)}\ell_{\ell}^{-}\bar{\nu}_{\ell})$, where $\ell$ is either electron or muon. We measure ${\cal{R}}(D) = 0.440 \pm 0.058 \pm 0.042$ and ${\cal{R}}(D^*) = 0.332 \pm 0.024 \pm 0.018$. These ratios exceed the Standard Model predictions by $2.0\sigma$ and $2.7\sigma$, respectively. The results disagree with the Standard Model predictions at the level of $3.4\sigma$. The ratios are sensitive to new physics contributions in the form of a charged Higgs boson. However, the access cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model.Comment: Contributed to the Proceedings of Hadron Collider Physics Symposium 2012, Kyoto, Japan, November 12-16 201

Measurements of |V_{cb}| and |V_{ub}| at BABAR

We report on new measurements of the Cabibbo-Kobayashi-Maskawa matrix elements |V_{cb}| and |V_{ub}| with inclusive and exclusive semileptonic B decays, highlighting the recent precision measurements with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC.Comment: Comments : Latex, 4 pages. Talk given at PANIC05: The Particles and Nuclei International Conference, October 24-28, 2005 Santa Fe, USA. Proceedings to appear in the American Institute of Physic

Hot Topics From BABAR Experiment

We search for a new light non-Standard Model CP-odd Higgs boson, $A^0$, decaying to $\tau^+\tau^-$, $\mu^+\mu^-$, and invisible in radiative decays of the $\Upsilon(2S)$ and $\Upsilon(3S)$. We search for the light scalar particle produced in single-photon decays of the $\Upsilon(3S)$ resonance through the process $\Upsilon(3S) \to \gamma A^0, A^0 \to$ invisible. We also search for evidence of an undetectable $\Upsilon(1S)$ decay recoiling against the dipion system. The data samples contain $99 \times 10^6 \Upsilon(2S)$ and $122 \times 10^6 \Upsilon(3S)$ decays collected by the \babar\ detector at the SLAC PEP-II $B$ factory.Comment: Contributed to the Proceedings of 16th International Seminar on High Energy Physics QUARKS-2010, Kolomna, Russia, 6-12 June, 201

Charm Decays and Spectroscopy at BABAR

We present searches for rare charm decays of the form $X_c^+ \to h^{\pm} \ell^{\mp} \ell^{(')^+}$, where $X_c^+$ is a charm hadron either $D^+$, $D_s^+$, or $\Lambda_c^+$, and $\ell^{(')^{\pm}}$ is an electron or muon. These modes are based on 384 $fb^{-1}$ of $e^+ e^-$ annihilation data collected at the $\Upsilon(4S)$ resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We also present the flavor-changing neutral-current decays $D^0 \to e^+e^-$, $D^0 \to \mu^+ \mu^-$, and $D^0 \to e^{\pm} \mu^{\mp}$ that corresponds to an integrated luminosity of 468 $fb^{-1}$ of data. The decay $D^0 \to e^+ \mu^-$ is further lepton-flavor violating, and thus occur only through very slow neutrino mixing. These decays constitute sensitive probes for possible new-physics contribution. We report new limits on the branching fractions of these decays.Comment: Contributed to the Proceedings of 36th International Conference on High Energy Physics, July 4-11, 2012, Melbourne, Australia. This work was supported by the U.S. Department of Energy under grant No. DE-FG02-96ER-4097

Measurements of |V_{cb}| and |V_{ub}| at BaBar

We report on new measurements of the Cabibbo-Kobayashi-Maskawa matrix elements |V{sub cb}| and |V{sub ub}| with inclusive and exclusive semileptonic B decays, highlighting the recent precision measurements with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC