59 research outputs found

    Fixed target Drell-Yan data and NNLO QCD fits of parton distribution functions

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    We discuss the influence of fixed target Drell-Yan data on the extraction of parton distribution functions at next-to-next-to-leading order (NNLO) in QCD. When used in a parton distribution fit, the Drell-Yan (DY) data constrain sea quark distributions at large values of Bjorken x. We find that not all available DY data are useful for improving the precision of parton distribution functions (PDFs) obtained from a fit to the deep inelastic scattering (DIS) data. In particular, some inconsistencies between DIS-based parton distribution functions and DY data for large values of dilepton rapidity are found. However, by selecting a sample of the DY data that is both representative and consistent with the DIS data, we are able to perform a combined PDF fit that significantly improves the precision of non-strange quark distributions at large values of x. The NNLO QCD corrections to the DY process are crucial for improving the precision. They reduce the uncertainty of the theoretical prediction, making it comparable to the experimental uncertainty in DY cross-sections over a broad range of x.Comment: 12 pages, revte

    Numerical Simulation of the Microtron Electron Beam Absorption by the Modified ABS-Plastic

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    Each specific task of the electron beam application imposes requirements for the beam profile and shape. One of the methods allows achieving high accuracy and low cost of the filters production is the 3D print method. The required properties of the electron beam interaction with the material can be achieved by using the modified plastic filaments. In this paper, the results of the model creation of the electron beams interaction with the ABS-plastic doped with different concentrations are presented. The depth dose distributions of the electron beam in the modified ABS-plastic are sown. The electron beam profiles and the electron beam distribution in the modified ABS-plastic are illustrated

    Climatic Factors Influencing the Anthrax Outbreak of 2016 in Siberia, Russia

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    In 2016, an outbreak of anthrax killing thousands of reindeer and affecting dozens of humans occurred on the Yamal peninsula, Northwest Siberia, after 70 years of epidemiological situation without outbreaks. The trigger of the outbreak has been ascribed to the activation of spores due to permafrost thaw that was accelerated during the summer heat wave. The focus of our study is on the dynamics of local environmental factors in connection with the observed anthrax revival. We show that permafrost was thawing rapidly for already 6 years before the outbreak. During 2011-2016, relatively warm years were followed by cold years with a thick snow cover, preventing freezing of the soil. Furthermore, the spread of anthrax was likely intensified by an extremely dry summer of 2016. Concurrent with the long-term decreasing trend in the regional annual precipitation, the rainfall in July 2016 was less than 10% of its 30-year mean value. We conclude that epidemiological situation of anthrax in the previously contaminated Arctic regions requires monitoring of climatic factors such as warming and precipitation extremes.Peer reviewe
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