29,432 research outputs found

    Transverse Energy and Minijets in High Energy Collisions

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    Minijet production and transverse energy are important not only to understand hadronic collisions, but also for the interpretation of nucleus collisions at RHIC and LHC, where it determines the ``initial conditions'' for the flow in a hadronic soup or a plasma. For high collision energies and small qT (minijets) we enter the BFKL region. This implies that we must take into account off-shell parton cross sections and non-integrated structure functions (kT-factorization). It is also essential to avoid double counting, as one emitted parton is a participant in two different subcollisions. The LDC model, developed in Lund to describe DIS, provides a very convenient formalism to handle these problems. The result is a dynamical suppression of minijets for small qT. The resulting transverse energy flow is similar to the result from a ''naive'' calculation based on integrated structure functions with a qT cut-off around 2 GeV.Comment: 6 pages, 7 figures, uses ws-p8-50x6-00.cls, contributed paper to the Proceedings of the XXXth International Symposium on Multiparticle Dynamics, Tihany, Hungary, October 200

    Fluctuations and Fermi-Dirac Correlations in e+e- annihilation

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    In this talk I first present a short review of fluctuations in e+e−e^+e^--annihilations. I then describe some new results on FD correlations. Experimental analyses of pppp and ΛΛ\Lambda\Lambda correlations indicate a very small production radius. This result relies very strongly on comparisons with MC simulations. A study of the approximations and uncertainties is these simulations imply that it is premature to draw such a conclusion from the data.Comment: Talk presented at XXXVI Int. Symp. on Multiparticle Dynamics, Paraty, Brazil, 2 - 8 Sept. 200

    Choosing the best of both worlds

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    The great crested newt (Triturus cristatus) is dependent on two environments for its survival: the aquatic habitat necessary for breeding and development, and the terrestrial habitat required for post-breeding and juvenile activities. For a population to be able to survive in a landscape, both habitat types must be present within migration distance from each other. The overall aim of this thesis is to find and describe prerequisites of environments and landscapes that make them sufficient as habitats for the great crested newt. The purpose is also to present the results in a conservation perspective and to discuss them in relation to practical examples. In five separate studies, performed in Örebro County, south-central Sweden, the aquatic and terrestrial habitats of the species were examined. The first study examined aquatic plants in a variety of ponds and landscapes, to determine if the diversity of plant species was higher in ponds where great crested newts were present. I found that ponds with newts had a significantly higher mean number of plant species than ponds without the species. The second study focused on the question if there are chemical and physical characteristics that determine occurrence of great crested newts. The results showed that temperature and nutrient levels (nitrogen and phosphorus) were important in distinguishing between ponds with and without newts, whereas other physical variables were less important. My results also suggest that the great crested newt selects ponds with low nutrient levels for breeding, while the species may also be present in ponds with higher nutrient levels. The third study used radio-telemetry in an attempt to determine how the great crested newt moved in its terrestrial habitat and which micro-habitats it used while the focal point of study four was the landscape and if landscape composition may predict use of ponds as aquatic habitats. Combined, studies three and four suggest that management of the species should to a greater extent include terrestrial habitat, with special attention given to older, deciduous-rich forest within approximately 200 m of breeding ponds. The aim of the last study was to describe and evaluate a project concerning translocation of a great crested newt population. I point out the necessity of long-term monitoring to distinguish any possible success with respect to site sustainability and population size

    Book Review: Chopsticks and Gambling, by Desmond Lam, Ph.D.

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    Book Review: Desmond Lam. Chopsticks and Gambling. Transaction Publishers, 2014. 172pp. (Cloth) ISBN 978-4128-5393-

    he geometry of statistical efficiency

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    We will place certain parts of the theory of statistical efficiency into the author’s operator trigonometry (1967), thereby providing new geometrical understanding of statistical efficiency. Important earlier results of Bloomfield and Watson, Durbin and Kendall, Rao and Rao, will be so interpreted. For example, worse case relative least squares efficiency corresponds to and is achieved by the maximal turning antieigenvectors of the covariance matrix. Some little-known historical perspectives will also be exposed. The overall view will be emphasized

    Unintegrated Parton Densities and Applications

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    Different formalisms for unintegrated parton densities are discussed, and some results and applications are presented.Comment: Talk presented at the Ringberg Workshop, New Trends in HERA Physics, Schloss Ringberg, Germany, 28 Sept. - 3 Oct. 200

    A Simple Model for the BFKL-DGLAP Transition

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    A simple model for the gluon structure function at small xx is presented, which gives an intuitive picture of the transition between the DGLAP and B FKL regimes.Comment: 4 pages, 2 figures (in eps) talk given at XXXI International Symposium on Multiparticle Dynamics, Sep. 1-7, 2001, Datong China URL http://ismd31.ccnu.edu.cn
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