1,339 research outputs found

    The complete mitochondrial genome of Isonychia kiangsinensis (Ephemeroptera: Isonychiidae)

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    The complete mitochondrial genome of Isonychia kiangsinensis is a circular molecule of 15,456 bp in length, containing 2 rRNA genes, 13 protein-coding genes, 22 tRNA genes, and a control region. The AT content of the overall base composition is 62.9%. The length of the control region for I. kiangsinensis is 745 bp with 68.6% AT content. In BI and ML phylogenetic trees, Isonychia kiangsinensis was a sister clade to I. ignota and Isonychiidae was shown to be the basal clade of Ephemeroptera excluding Siphluriscidae. The monophyly of the families Isonychiidae, Heptageniidae, Viemamellidae, and Baetidae and the genus Isonychia were well supported

    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 the Total Cross Section for Hadronic Production by e+e- Annihilation at Energies between 2.6-5 Gev

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    Using the upgraded Beijing Spectrometer (BESII), we have measured the total cross section for e+ee^+e^- annihilation into hadronic final states at center-of-mass energies of 2.6, 3.2, 3.4, 3.55, 4.6 and 5.0 GeV. Values of RR, σ(e+ehadrons)/σ(e+eμ+μ)\sigma(e^+e^-\to {hadrons})/\sigma(e^+e^-\to\mu^+\mu^-), are determined.Comment: Submitted to Phys. Rev. Let

    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

    Measurements of ψ(2S)\psi(2S) decays into Vector- Tensor final states

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    Decays of the ψ(2S)\psi(2S) into vector plus tensor meson final states have been studied with 14 million ψ(2S)\psi(2S) events collected with the BESII detector. Branching fractions of \psi(2S) \rt \omega f_{2}(1270), ρa2(1320)\rho a_2(1320), K(892)0Kˉ2(1430)0+c.c.K^*(892)^0\bar{K}^*_2(1430)^0+c.c. and ϕf2(1525)\phi f_2^{\prime}(1525) are determined. They improve upon previous BESI results and confirm the violation of the "12%" rule for ψ(2S)\psi(2S) decays to VT channels with higher precision.Comment: 7 pages, 7 figures and 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

    A side-by-side comparison of Daya Bay antineutrino detectors

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    The Daya Bay Reactor Neutrino Experiment is designed to determine precisely the neutrino mixing angle θ13\theta_{13} with a sensitivity better than 0.01 in the parameter sin22θ13^22\theta_{13} at the 90% confidence level. To achieve this goal, the collaboration will build eight functionally identical antineutrino detectors. The first two detectors have been constructed, installed and commissioned in Experimental Hall 1, with steady data-taking beginning September 23, 2011. A comparison of the data collected over the subsequent three months indicates that the detectors are functionally identical, and that detector-related systematic uncertainties exceed requirements.Comment: 24 pages, 36 figure

    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

    A new measurement of antineutrino oscillation with the full detector configuration at Daya Bay

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    We report a new measurement of electron antineutrino disappearance using the fully-constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×\times105^5 GWth_{\rm th}-ton-days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six 241^{241}Am-13^{13}C radioactive calibration sources reduced the background by a factor of two for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin22θ13\sin^{2}2\theta_{13} and Δmee2|\Delta m^2_{ee}| were halved as a result of these improvements. Analysis of the relative antineutrino rates and energy spectra between detectors gave sin22θ13=0.084±0.005\sin^{2}2\theta_{13} = 0.084\pm0.005 and Δmee2=(2.42±0.11)×103|\Delta m^{2}_{ee}|= (2.42\pm0.11) \times 10^{-3} eV2^2 in the three-neutrino framework.Comment: Updated to match final published versio
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