Electroweak measurements in electron–positron collisions at w-boson-pair energies at lep

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Search for Charged Higgs bosons: Combined Results Using LEP Data

The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for pair-produced charged Higgs bosons in the framework of Two Higgs Doublet Models (2HDMs). The data of the four experiments are statistically combined. The results are interpreted within the 2HDM for Type I and Type II benchmark scenarios. No statistically significant excess has been observed when compared to the Standard Model background prediction, and the combined LEP data exclude large regions of the model parameter space. Charged Higgs bosons with mass below 80 GeV/c^2 (Type II scenario) or 72.5 GeV/c^2 (Type I scenario, for pseudo-scalar masses above 12 GeV/c^2) are excluded at the 95% confidence level

Evidence for b→dγb \to d \gamma Transitions From a Sum of Exclusive Final States in the Hadronic Final State Mass Range 1.0GeV/c2<M(Xd)<1.8GeV/c21.0 {GeV}/c^2< M(X_d)<1.8 {GeV}/c^2

16 pages, 7 postscript figures, contributed to the XXIIIrd International Symposium on Lepton and Photon Interactions at High Energies, 8/13 – 8/18/2007, Daegu, KoreaWe present preliminary results of a search for $B\to X_d\gamma$ decays with a hadronic mass 1.0 GeV/$c^

Measurement of the B0→Xu−ℓ+νℓB^0\to X_{u}^- \ell^+ {\nu_\ell} decays near the kinematic endpoint of the lepton spectrum and search for violation of isospin symmetry

17 pages, 8 postscript figures, submitted to Lepton Photon 2007 - Contributed to the XXIIIrd International Symposium on Lepton and Photon Interactions at High Energies, 8/13 – 8/18/2007, Daegu, KoreaWe present the first measurement of the $B^0\to X_{u}^- \ell^+ {\nu_\ell}$ partial branching fraction in the end-point region of the lepton momentum spectrum, above the threshold for $B\to X_c\ell {\nu_\ell}$ decays. The analysis is based on a sample of 383 million $\Upsilon(4S)$ decays into $B{\bar B}$ pairs collected with the {\sc BaBar} detector at the PEP-II $e^+e^-$ storage rings. We select $B^0{\bar B}^0$ events by partially reconstructing one \B meson via the ${\bar B}^0\to D^{*+} \ell^- \bar{\nu}_\ell$ decays then select $B^0\to X_{u}^- \ell^+ {\nu_\ell}$ decays identifying a second high momentum lepton. In the momentum interval ranging from 2.3 to 2.6 GeV/c we measure the partial branching fraction $\Delta{\cal B}(B^0\to X_u\ell\nu)=(1.30\pm0.21_{stat}\pm0.07_{syst})\times 10^{-4}$ where the first error is statistical and the second is systematic. By comparing this measurement with the one obtained from untagged B decays we obtain $R^{+/0}=\Delta{\cal B}(B^0\to X_u\ell\nu)/\Delta{\cal B}(B^+\to X_u\ell\nu)= 1.18 \pm 0.35_{stat} \pm 0.17_{syst}$. Using this measurement we extract a limit on the contributions from processes breaking isospin symmetry in charmless semileptonic B decays

Measurement of the Branching Fractions of Exclusive \barB \to D/D*/D(*) \pi \ell^- \bar{\nu}_{\ell} Decays in Events Tagged by a Fully Reconstructed B Meson

19 pages, 3 postscript figures, submitted to XXIIIrd International Symposium on Lepton and Photon Interactions at High Energies, 8/13 -- 8/18/2007, Daegu, KoreaWe present a measurement of the branching fractions for anti-B -> D/D*/D(*) pi l^- anti-nu_l decays based on 341.1 fb-1 of data collected at the Upsilon(4S) resonance with the BaBar detector at the pep-II e^+e^- storage rings. Events are tagged by fully reconstructing one of the B mesons in a hadronic decay mode. We obtain BF (B^- -> D^0 l^- anti-nu_l) = (2.33 +/- 0.09(stat.) +/- 0.09(syst.))%, BF (B^- -> D^*0 l^- anti-nu_l) = (5.83 +/- 0.15(stat.) +/- 0.30(syst.))%, BF (B0bar -> D^+ l^- anti-nu_l) = (2.21 +/- 0.11(stat.) +/- 0.12(syst.))%, BF (B0bar -> D^*+ l^- anti-nu_l) = (5.49 +/- 0.16(stat.) +/- 0.25(syst.))%, BF (B^- -> D^+ pi^- l^- anti-nu_l) = (0.42 +/- 0.06(stat.) +/- 0.03(syst.))%, BF (B^- -> D^*+ pi^- l^- anti-nu_l) = (0.59 +/- 0.05(stat.) +/- 0.04(syst.))%, BF (B0bar -> D^0 pi^+ l^- anti-nu_l) = (0.43 +/- 0.08(stat.) +/- 0.03(syst.))% and BF (B0bar -> D^*0 pi^+ l^- anti-nu_l) = (0.48 +/- 0.08(stat.) +/- 0.04(syst.))%

Improved Measurement of the Cabibbo-Kobayashi-Maskawa Angle α Using B0(B¯)→ρ+ρ- Decays

We present results from an analysis of B0(B̅ 0)→ρ+ρ- using 232×106 Υ(4S)→BB̅ decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We measure the longitudinal polarization fraction fL=0.978±0.014(stat)+0.021/-0.029(syst) and the CP-violating parameters SL=-0.33±0.24(stat)+0.08/-0.14(syst) and CL=-0.03±0.18(stat)±0.09(syst). Using an isospin analysis of B→ρρ decays, we determine the unitarity triangle parameter α. The solution compatible with the standard model is α=(100±13)°

Improved measurement of the Cabibbo-Kobayashi-Maskawa angle α using B0(B)→p+p- decays

We present results from an analysis of B0(B¯¯¯0)→ρ+ρ− using 232×106 Υ(4S)→BB¯¯¯ decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We measure the longitudinal polarization fraction fL=0.978±0.014(stat)+0.021−0.029(syst) and the CP-violating parameters SL=−0.33±0.24(stat)+0.08−0.14(syst) and CL=−0.03±0.18(stat)±0.09(syst). Using an isospin analysis of B→ρρ decays, we determine the unitarity triangle parameter α. The solution compatible with the standard model is α=(100±13)°