22 research outputs found

    The Physics of the B Factories

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    This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

    Metal-induced stress in survivor plants following the end-Permian collapse of land ecosystems

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    Teratological spores and pollen are widespread in sediments that record the Permian-Triassic mass extinction. The malformations are thought to be the result of extreme environmental conditions at that time, but the mutagenic agents and the precise timing of the events remain unclear. We examined the abundance of teratological sporomorphs and metal concentrations in a Permian-Triassic tropical peatland succession of southwestern China. We find a significant peak of spore tetrads of lycopsid plants (as much as 19% of all sporomorphs) coeval with increases in Cu and Hg concentrations above the main terrestrial extinction interval, which marks the loss of Permian Gigantopteris forests, increased wildfire activity, and the disappearance of coal beds. Thus, in tropical peatlands, mutagenesis affected only surviving plants. Mutagenesis was likely caused by metal toxicity, linked to increased Hg and Cu loading, but was not itself a direct cause of the terrestrial crisis

    Metal-induced stress in survivor plants following the end-Permian collapse of land ecosystems

    Get PDF
    Teratological spores and pollen are widespread in sediments that record the Permian-Triassic mass extinction. The malformations are thought to be the result of extreme environmental conditions at that time, but the mutagenic agents and the precise timing of the events remain unclear. We examined the abundance of teratological sporomorphs and metal concentrations in a Permian-Triassic tropical peatland succession of southwestern China. We find a significant peak of spore tetrads of lycopsid plants (as much as 19% of all sporomorphs) coeval with increases in Cu and Hg concentrations above the main terrestrial extinction interval, which marks the loss of Permian Gigantopteris forests, increased wildfire activity, and the disappearance of coal beds. Thus, in tropical peatlands, mutagenesis affected only surviving plants. Mutagenesis was likely caused by metal toxicity, linked to increased Hg and Cu loading, but was not itself a direct cause of the terrestrial crisis

    F-2(D(3)) measurements at ZEUS

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    Results on the diffractive structure function F-2(D(3)) in deep inelastic neutral current positron-proton scattering (DIS) have been obtained by the ZEUS collaboration using two different methods. Diffractive interactions are selected by either requiring a small, not exponentially suppressed invariant hadronic mass M-X in the main detector or by detecting a fast proton in the ZEUS leading proton spectrometer (LPS). The results of the two methods are compared

    Recent photoproduction results from ZEUS

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    Recent results for inclusive jet cross sections, dijet cross sections and dijet angular distributions are compared with NLO perturbative QCD calculations. The observation of isolated high PT photons (prompt photons) is also reported

    Leading baryons at low x(L) in DIS and photoproduction at ZEUS

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    Results obtained by the ZEUS collaboration on leading baryon production in the proton fragmentation region are presented. The reaction gamma p --> NX, with N a proton or a neutron, is examined both at low and high photon virtuality

    Event shape analysis of multihadronic final states in deep inelastic rapidity gap events at HERA

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    A global event shape analysis of the multihadronic final states observed in deep inelastic scattering (DIS) with a large forward rapidity gap (LRG) is performed in the range Q(2) greater than or equal to 5 GeV2, 160 GeV less than or equal to W less than or equal to 250 GeV and eta(max) less than or equal to 1.8. Particular emphasis is paid to the dependence of these variables, measured in the gamma*-pomeron rest frame, upon M-X, the mass of the hadronic final state. With increasing M-X the multihadronic final states become planar. The broadening effects exhibited by the data can be described by including a gluon density in models where the pomeron has a partonic structure or alternatively by considering a direct coupling of the pomeron to quark and gluon pairs
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