Results 1 - 10 of 8367
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[en] We discuss B0 - B-bar0 mixing and CP violation in the minimal left-right symmetric model. While the amount of mixing is not much changed with respect to the standard model, left-right symmtery can give rise to significantly larger CP violation in the B0sub(s) - B-bar0sub(s) system. (Author)
[en] We present a search for the lepton flavor violating decay modes B± → h± τ(ell) (h = K, π; (ell) = e, μ) using the BABAR data sample, which corresponds to 472 million B(bar B) pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and (ell) candidates, we are able to fully determine the τ four-momentum. The resulting τ candidate mass is our main discriminant against combinatorial background. We see no evidence for B± → h± τ(ell) decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10-5.
[en] We report a measurement of the inclusive semileptonic branching fraction of the Bs meson using data collected with the BABAR detector in the center-of-mass energy region above the γ(4S) resonance. We use the inclusive yield of φ mesons and the φ yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of Bs mesons relative to all B mesons as a function of center-of-mass energy. The inclusive semileptonic branching fraction of the Bs meson is determined to be Β(Bs → (ell)νX) = 9.5-2.0+2.5(stat)-1.9+1.1(syst)%, where (ell) indicates the average of e and μ.
[en] The authors present a search for the decay B+ → (ell)+ν#ell# ((ell) = τ, μ, or e) in (458.9 ± 5.1) x 106 B(bar B) pairs recorded with the BABAR detector at the PEP-II B-Factory. They search for these B decays in a sample of B+B- events where one B-meson is reconstructed as B- → D0(ell)-(bar ν)X. Using the method of Feldman and Cousins, they obtain Β(B+ → τ+ντ) = (1.7 ± 0.8 ± 0.2) x 10-4, which excludes zero at 2.3σ. They interpret the central value in the context of the Standard Model and find the B meson decay constant to be fB2 = (62 ± 31) x 103 MeV2. They find no evidence for B+ → e+νe and B+ → μ+νμ and set upper limits at the 90% C.L. Β(B+ → e+νe) < 0.8 x 10-5 and Β(B+ → μ+νμ) < 1.1 x 10-5.
[en] If significant numbers of B mesons are produced through one or more narrow excited (bar bq) states, the strong decay B**± → B(*)0π± will tag the neutral meson as (bar bd) or (b bar d), respectively. This might be dramatically more efficient than using the pair-produced partner of the B as a flavor tag, and could advance the search for the expected large CP-violating ambiguities in semileptonic decays of charged and neutral B mesons by choosing between two solutions for the momentum of the undetected neutrino. Estia Eichten, Chris Hill, and the author have used heavy-quark symmetry to estimate the masses, widths, and branching fractions of orbitally excited B, Ds, and Bs states from the properties of corresponding K and D levels. Their analysis shows that one requirement for the utility of B**-tagging - narrow resonances - is likely to be met by the B2* and B1. Experiment will have to rule on the strength of these lines and the ratio of signal to background
[en] The organizers of this workshop tell the author that this overview paper should be a personal, biased view of where we are and where we are going in the B-factory endeavor. In this paper after a few words on the physics and on the detector, the author spends most of the author's time discussing the machine. The author ends with a parable, and a moral to be drawn from it
[en] The authors summarize measurements of the CKM angle β at the B-factories emphasizing a comparison of β measured in the B0 → c(bar c)K(*)0 decay channels and βeff measured in b → q(bar q)s decay channels, such as B0 → ωKs0, B0 → η'K0, B0 → π0KS0, and B0 → s0 KS0KS0.
[en] The authors describe the present status of the PEP-II asymmetric B factory design undertaken by SLAC, LBL, and LLNL. Design optimization and changes from the original CDR are described. R ampersand D activities have focused primarily on the key technology areas of vacuum, RF, and feedback system design. Recent progress in these areas is described. The R ampersand D results have verified their design assumptions and provide further confidence in the design of PEP-II
[en] The mass spectrum of the bar bc system is considered in potential models for heavy quarkonia. Spin-dependent splittings of bar bc-quarkonium levels are calculated with allowance for a change in the constant of the effective Coulomb interaction between the quarks. The widths of radiative transitions between the levels of this system are evaluated. The masses of the lightest vector Bc* and pseudoscalar Bc states are estimated using QCD sum rules. A scaling relation for the leptonic constants of heavy quarkonia is derived, and the leptonic constant fBc is evaluated. 33 refs., 14 figs
[en] 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 Β(B → D(*)τν) and the ratio Β(B → D(*)τν)/Β(B → D(*)(ell)ν) is presented. For the D* mode, a branching fraction of 1.79 ± 0.13(stat) ± 0.17(syst) is found, with a ratio of 0.325 ± 0.023(stat) ± 0.027(syst). For the D mode, the results are 1.04 ± 0.12(stat) ± 0.14(syst) and 0.456 ± 0.053(stat) ± 0.056(syst), respectively. In addition, a study of Bs production and semileptonic decays using data collected in a center-of-mass energy region above the Υ(4S) resonance is discussed. The semileptonic branching fraction Β(Bs → (ell)νX) is measured to be 9.9-2.1+2.6(stat)-2.0+1.3(syst).