4,431 research outputs found

    Measurement of the total cross section for e^+e^-→hadrons at √s=10.52 GeV

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    Using the CLEO detector at the Cornell Electron Storage Ring, we have made a measurement of R≡σ(e^+e^-→hadrons)/σ(e^+e^-→μ^+μ^-)=3.56±0.01±0.07 at √s=10.52 GeV. This implies a value for the strong coupling constant of α_s(10.52 GeV)=0.20±0.01±0.06, or α_s(MZ)=0.13±0.005±0.03

    Baló’s concentric sclerosis is immunologically distinct from multiple sclerosis: results from retrospective analysis of almost 150 lumbar punctures

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    Background: Baló’s concentric sclerosis (BCS) is a rare inflammatory demyelinating disorder of the central nervous system characterised by concentric layers of demyelination. It is unclear whether BCS is a variant of multiple sclerosis (MS) or a disease entity in its own right. Objective: To compare the cerebrospinal fluid (CSF) features of BCS to those of MS. Methods: Retrospective analysis of the CSF profile of all patients with BCS reported in the medical literature between 1980 and 2017. Results: In total, the results of 146 lumbar punctures (LP) in 132 patients were analysed. The most striking finding was a lack of CSF-restricted oligoclonal bands (OCB) in 66% (56/85) of all LP in the total BCS group, in 74% (14/19) in the subgroup of patients with both MRI and histological evidence for BCS, and in 82% (18/22) in the subgroup of patients with highest radiological confidence (high MRI quality, ≥ 3 layers of demyelination). OCB disappeared in 1/2 initially OCB-positive patients. These findings are in stark contrast to MS, in which OCB are present in ≥ 95% of patients and are thought to remain stably detectable over the entire course of disease (p < 0.000001). OCB frequency was low both in ‘historic’ patients (1980–2009; 37%) and in more recent patients (2010–2017; 31%). OCB-positive and OCB-negative patients did not differ significantly with regard to age, sex, disease duration, number of Baló-like lesions on MRI, number of relapses, treatment or final outcome. In accordance with the high rate of OCB negativity, Link’s IgG index was negative in 63% of all tested samples (p < 0.000001 vs. MS). CSF pleocytosis was present in 28% (27/96; p < 0.000001 vs. MS) and elevated CSF total protein levels in 41% (31/76) of samples. Conclusion: OCB and IgG index frequencies in BCS are much more similar to those reported in neuromyelitis optica or myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis than to those in MS. Our findings suggest that in most cases BCS-like lesions denote the presence of a disease entity immunologically distinct from MS. In addition, we provide data on the demographics, clinical course and radiological features of BCS based on the largest cohort analysed to date

    Indications for Factorization and ReVub<0Re V_{ub} < 0 from Rare B Decay Data

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    Surveying known hadronic rare B decays, we find that the factorization approximation can give a coherent account of KπK\pi, ππ\pi\pi and ρ0π+\rho^0\pi^+ data and give predictions for ω0π+\omega^0\pi^+, ρπ\rho\pi and KπK^*\pi modes, {\it if ReVub{Re}V_{ub} is taken as negative} (in standard phase convention) rather than positive. As further confirmation, we expect a lower sin2β\sin2\beta value at B Factories as compared to current fits, and BsB_s mixing close to LEP bounds at SLD and CDF.Comment: 11 pages, revtex, 4 figures (unchanged and eps files included); version (including title and abstract change) to appear in Phys. Rev. Let

    Observation of the Dynamic Beta Effect at CESR with CLEO

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    Using the silicon strip detector of the CLEO experiment operating at the Cornell Electron-positron Storage Ring (CESR), we have observed that the horizontal size of the luminous region decreases in the presence of the beam-beam interaction from what is expected without the beam-beam interaction. The dependence on the bunch current agrees with the prediction of the dynamic beta effect. This is the first direct observation of the effect.Comment: 9 page uuencoded postscript file, postscritp file also available through http://w4.lns.cornell.edu/public/CLNS, submitted to Phys. Rev.

    New Science on the Open Science Grid

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    The Open Science Grid (OSG) includes work to enable new science, new scientists, and new modalities in support of computationally based research. There are frequently significant sociological and organizational changes required in transformation from the existing to the new. OSG leverages its deliverables to the large scale physics experiment member communities to benefit new communities at all scales through activities in education, engagement and the distributed facility. As a partner to the poster and tutorial at SciDAC 2008, this paper gives both a brief general description and some specific examples of new science enabled on the OSG. More information is available at the OSG web site: (http://www.opensciencegrid.org)

    Precision Measurement of the Ds+Ds+D_s^{*+}- D_s^+ Mass Difference

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    We have measured the vector-pseudoscalar mass splitting M(Ds+)M(Ds+)=144.22±0.47±0.37MeVM(D_s^{*+})-M(D_s^+) = 144.22\pm 0.47\pm 0.37 MeV, significantly more precise than the previous world average. We minimize the systematic errors by also measuring the vector-pseudoscalar mass difference M(D0)M(D0)M(D^{*0})-M(D^0) using the radiative decay D0D0γD^{*0}\rightarrow D^0\gamma, obtaining [M(Ds+)M(Ds+)][M(D0)M(D0)]=2.09±0.47±0.37MeV[M(D_s^{*+})-M(D_s^+)]-[M(D^{*0})-M(D^0)] = 2.09\pm 0.47\pm 0.37 MeV. This is then combined with our previous high-precision measurement of M(D0)M(D0)M(D^{*0})-M(D^0), which used the decay D0D0π0D^{*0}\rightarrow D^0\pi^0. We also measure the mass difference M(Ds+)M(D+)=99.5±0.6±0.3M(D_s^+)-M(D^+)=99.5\pm 0.6\pm 0.3 MeV, using the ϕπ+\phi\pi^+ decay modes of the Ds+D_s^+ and D+D^+ mesons.Comment: 18 pages uuencoded compressed postscript (process with uudecode then gunzip). hardcopies with figures can be obtained by sending mail to: [email protected]

    Flavor-Specific Inclusive B Decays to Charm

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    We have measured the branching fractions for B -> D_bar X, B -> D X, and B -> D_bar X \ell^+ \nu, where ``B'' is an average over B^0 and B^+, ``D'' is a sum over D^0 and D^+, and``D_bar'' is a sum over D^0_bar and D^-. From these results and some previously measured branching fractions, we obtain Br(b -> c c_bar s) = (21.9 ±\pm 3.7)%, Br(b -> s g) K^- \pi^+) = (3.69 ±\pm 0.20)%. Implications for the ``B semileptonic decay problem'' (measured branching fraction being below theoretical expectations) are discussed. The increase in the value of Br(b -> c c_bar s) due to B>DXB -> D X eliminates 40% of the discrepancy.Comment: 12 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Semileptonic Branching Fraction of Charged and Neutral B Mesons

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    An examination of leptons in Υ(4S){\Upsilon (4S)} events tagged by reconstructed BB decays yields semileptonic branching fractions of b=(10.1±1.8±1.4)%b_-=(10.1 \pm 1.8\pm 1.4)\% for charged and b0=(10.9±0.7±1.1)%b_0=(10.9 \pm 0.7\pm 1.1)\% for neutral BB mesons. This is the first measurement for charged BB. Assuming equality of the charged and neutral semileptonic widths, the ratio b/b0=0.93±0.18±0.12b_-/b_0=0.93 \pm 0.18 \pm 0.12 is equivalent to the ratio of lifetimes. A postscript version is available through World-Wide-Web in http://w4.lns.cornell.edu/public/CLNS/1994Comment: 9 pages (in REVTEX format) Preprint CLNS94-1286, CLEO 94-1

    First Observation of Υ(1S)γππ\Upsilon(1S)\to \gamma\pi\pi

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    We report on a study of exclusive radiative decays of the Upsilon(1S) resonance collected with the CLEO-II detector operating at CESR. We present the first observation of the radiative decays Upsilon(1S)->gamma pi+pi- and Upsilon(1S)->gamma pi0pi0. For the dipion mass regime m(pipi)>1.0 GeV, we obtain Br(Upsilon(1S)->gamma pi+pi-=(6.3+/-1.2+/-1.3) x 10^(-5), and Br(Upsilon(1S)->gamma pi0pi0=(1.7+/-0.6+/-0.3) x 10^(-5). The observed gamma pipi events are consistent with the hypothesis Upsilon(1S)->gamma f2(1270).Comment: 9 pages, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Observation of a New Charmed Strange Meson

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    Using the CLEO-II detector, we have obtained evidence for a new meson decaying to D0K+D^0 K^+. Its mass is 2573.21.6+1.7±0.8±0.52573.2^{+1.7}_{-1.6}\pm 0.8\pm 0.5 {}~MeV/c2c^2 and its width is 164+5±316^{+5}_{-4}\pm 3~MeV/c2c^2. Although we do not establish its spin and parity, the new meson is consistent with predictions for an L=1L=1, S=1S=1, JP=2+J_P=2^+ charmed strange state.Comment: 9 pages uuencoded compressed postscript (process with uudecode then gunzip). hardcopies with figures can be obtained by sending mail to: [email protected]
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