1,720,993 research outputs found
Measurement of the Ratio of Charged and Neutral Mesons in Υ (4) Events via Partial Reconstruction of the Semileptonic Decays ̅⁰⟶<sup>∗</sup>⁺ℓ⁻<sub>̅ℓ</sub> and ̅⁻⟶<sup>∗</sup>⁰ℓ<sub>̅ℓ</sub>
No full textThe decays, and are studied using data collected at the CLEO II detector at the Cornell Electron Storage Ring. Both decays are identified using a partial reconstruction method where the D* is detected only through a pion daughter from the decay . Because of the similarities in the analyses of the two modes, the ratio of the rates is measured in a way that is independent of the decay model, limited mainly by the uncertainty in the relative efficiency for detecting neutral and charged pions. This ratio is equivalent to the ratio of the product of production fraction and lifetime for charged and neutral B mesons, .
It is combined with measurements of the lifetime ratio to obtain the ratio of charged and neutral B meson production at the Y(4S) resonance, .Ph. D
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Hot Topics From BaBar Experiment
Full text linkThe authors search for a new light non-Standard Model CP-odd Higgs boson, A{sup 0}, decaying to {tau}{sup +}{tau}{sup -}, {mu}{sup +}{mu}{sup -}, 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) {yields} {gamma}A{sup 0}, A{sup 0} {yields} invisible. We also search for evidence of an undetectable {Upsilon}(1S) decay recoiling against the dipion system. The data samples contain 99 x 10{sup 6} {Upsilon}(2S) and 122 x 10{sup 6} {Upsilon}(3S) decays collected by the BABAR detector at the SLAC PEP-II B factory
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Measurement of the Absolute Branching Fraction of D^0 to K^- \pi^+
No full textThe authors measure the absolute branching fraction for D{sup 0} {yields} K{sup -} {pi}{sup +} using partial reconstruction of {bar B}{sup 0} {yields} D*{sup +} X {ell}{sup -} {bar {nu}}{sub {ell}} decays. Only the charged lepton and the soft pion from the decay D*{sup +} {yields} D{sup 0} {pi}{sup +} are used. Based on a data sample of 230 million B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, they obtain {Beta}(D{sup 0} {yields} K{sup -} {pi}{sup +}) = (4.025 {+-} 0.038 {+-} 0.098)%, where the first error is statistical and the second error is systematic
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Search For New Physics at BABAR*
No full textUsing a full BABAR data sample of 426 fb−1, we present improved measurements of the ratio ℛ(D(∗)) = ℬ(B̅ → D(∗)τ−ν̅τ)/ ℬ(B̅ → D(∗)ℓℓ−ν̅ℓ), where ℓ is either electron or muon. We measure ℛ(D) = 0.440±0.058±0.042 and ℛ(D∗) = 0.332±0.024±0.018. These ratios exceed the Standard Model predictions by 2:0σ and 2:7σ, respectively. The results disagree with the Standard Model predictions at the level of 3:4σ. 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
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Measurements of |V_{cb}| and |V_{ub}| at BaBar
Full text linkWe 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
Charm Decays and Spectroscopy at BABAR
Full text linkWe present searches for rare charm decays of the form X+c → h±ℓ∓ℓ(, where X+c is a charm hadron either D+, D+s, or Λ+c, and ℓ( ′) ± is an electron or muon. These modes are based on 384 f b−1 of e+e − annihilation data collected at the ϒ(4S) resonance with the BABAR detector at the SLAC National Accelerator Laboratory. We also present the flavor-changing neutral-current decays D0 → e+e−, D0 → µ+µ−, and D0 → e±µ ∓ that corresponds to an integrated luminosity of 468 f b−1 of data. The decay D0 → e+µ − 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Search for Muonic Dark Forces at BABAR
Full text linkMany models of physics beyond Standard Model predict the existence of light Higgs states, dark photons, and new gauge bosons mediating interactions between dark sectors and the Standard Model. Using a full data sample collected with the BABAR detector at the PEP-II e+e− collider, we report searches for a light non-Standard Model Higgs boson, dark photon, and a new muonic dark force mediated by a gauge boson (Z′) coupling only to the second and third lepton families. Our results significantly improve upon the current bounds and further constrain the remaining region of the allowed parameter space
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