384 research outputs found

    Measurement of J/ψ Production in Continuum e^+e^− Annihilations near √s = 10.6 GeV

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    The production of J/ψ mesons in continuum e^+e^− annihilations has been studied with the BABAR detector at energies near the Υ(4S) resonance. The mesons are distinguished from J/ψ production in B decays through their center-of-mass momentum and energy. We measure the cross section e^+e^− → J/ψX to be 2.52±0.21±0.21pb. We set a 90% C.L. upper limit on the branching fraction for direct Υ(4S) → J/ψX decays at 4.7×10^(-4)

    First Measurement of the Branching Fraction of the Decay psi(2S) --> tau tau

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    The branching fraction of the psi(2S) decay into tau pair has been measured for the first time using the BES detector at the Beijing Electron-Positron Collider. The result is Bττ=(2.71±0.43±0.55)×103B_{\tau\tau}=(2.71\pm 0.43 \pm 0.55) \times 10^{-3}, where the first error is statistical and the second is systematic. This value, along with those for the branching fractions into e+e- and mu+mu of this resonance, satisfy well the relation predicted by the sequential lepton hypothesis. Combining all these values with the leptonic width of the resonance the total width of the psi(2S) is determined to be (252±37)(252 \pm 37) keV.Comment: 9 pages, 2 figure

    Measurement of the Inclusive Charm Cross Section at 4.03 GeV and 4.14 GeV

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    The cross section for charmed meson production at s=4.03\sqrt{s} = 4.03 and 4.14 GeV has been measured with the Beijing Spectrometer. The measurement was made using 22.3 pb1pb^{-1} of e+ee^+e^- data collected at 4.03 GeV and 1.5 pb1pb^{-1} of e+ee^+e^- data collected at 4.14 GeV. Inclusive observed cross sections for the production of charged and neutral D mesons and momentum spectra are presented. Observed cross sections were radiatively corrected to obtain tree level cross sections. Measurements of the total hadronic cross section are obtained from the charmed meson cross section and an extrapolation of results from below the charm threshold.Comment: 11 pages, 13 figures. The top level tex file is paper.tex. It builds the paper from other tex files in this .tar and the .eps file

    Study of the P-wave charmonium state \chi_{cJ} in \psi(2S) decays

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    The processes ψ(2S)γπ+π\psi(2S)\to \gamma \pi^+ \pi^-, γK+K\gamma K^+ K^- and γppˉ\gamma p \bar{p} have been studied using a sample of 3.7×1063.7 \times 10^6 produced ψ(2S)\psi(2S) decays. We determine the total width of the χc0\chi_{c0} to be Γχc0tot=14.3±2.0±3.0\Gamma^{tot}_{\chi_{c0}} = 14.3\pm 2.0\pm 3.0 MeV. We present the first measurement of the branching fraction B(χc0ppˉ)=(16.3±4.4±5.4)×105B(\chi_{c0} \to p \bar{p}) = (16.3 \pm 4.4 \pm 5.4)\times 10^{-5}, where the first error is statistical and the second one systematic. Branching fractions of χc0,2π+π\chi_{c0,2} \to \pi^+ \pi^- and K+KK^+ K^- are also reported.Comment: 10 pages, revtex, 3 figures, 2 table

    Measurement of ψ(2S)\psi(2S) decays to baryon pairs

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    A sample of 3.95M ψ(2S)\psi(2S) decays registered in the BES detector are used to study final states containing pairs of octet and decuplet baryons. We report branching fractions for ψ(2S)ppˉ\psi(2S)\to p\bar{p}, ΛΛˉ\Lambda\bar{\Lambda}, Σ0Σˉ0\Sigma^0\bar{\Sigma}{}^0, ΞΞˉ+\Xi^-\bar{\Xi}{}^+, Δ++Δˉ\Delta^{++}\bar{\Delta}{}^{--}, Σ+(1385)Σˉ(1385)\Sigma^+(1385)\bar{\Sigma}{}^-(1385), Ξ0(1530)Ξˉ0(1530)\Xi^0(1530)\bar{\Xi}{}^0(1530), and ΩΩˉ+\Omega^-\bar{\Omega}{}^+. These results are compared to expectations based on the SU(3)-flavor symmetry, factorization, and perturbative QCD.Comment: 22 pages, 21 figures, 4 table

    Crowdsourced estimation of cognitive decline and resilience in Alzheimer's disease

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    Identifying accurate biomarkers of cognitive decline is essential for advancing early diagnosis and prevention therapies in Alzheimer's disease. The Alzheimer's disease DREAM Challenge was designed as a computational crowdsourced project to benchmark the current state-of-the-art in predicting cognitive outcomes in Alzheimer's disease based on high dimensional, publicly available genetic and structural imaging data. This meta-analysis failed to identify a meaningful predictor developed from either data modality, suggesting that alternate approaches should be considered for prediction of cognitive performance
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