8,930 research outputs found

    BaBar simulation production - A millennium of work in under a year

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    The BaBar experiment requires simulated events beyond the ability of a single computing site to provide. This paper describes the evolution of simulation and job management methods to meet the physics community requirements and how production became distributed to use resources beyond any one computing center. The evolution of BaBar simulation along with the development of the distribution of the computing effort is described. As the computing effort is distributed to more sites there is a need to simplify production so the effort does not multiply with number of production centers. Tools are created to be flexible in handling errors and failures that happen in the system and respond accordingly, this reduces failure rates and production effort. This paper will focus on one cycle of simulation production within BaBar as a description of a large scale computing effort which was fully performed, and provided new simulation data to the users on time

    Threshold Effects in Slepton-Pair Production at the LHC

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    We present a study of threshold resummation effects for slepton pair production at the Large Hadron Collider (LHC). After confirming the known NLO QCD corrections and generalizing the NLO SUSY-QCD corrections to the case of mixing squarks in the virtual loop contributions, we employ the Mellin N-space resummation formalism to compute logarithmically enhanced soft-gluon terms to all perturbative orders.Comment: 3 pages, 1 figure, presented at HEP 2007 (Manchester, July 2007

    Sistema di filologia computazionale per testi demotici

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    A project for a Demotic Inscriptions on Ostraka Database is being carried out in collaboration between ILC/CNR (Pisa), the Department of Electronic Engineering (Calabria University) and the Department of the Ancient World History (Egyptological section, Pisa University). The aim of the project is to analyse the digital colour images of demotic texts on ostraka (Medinet Madi, in Fayyum region) with the aid of computational tools. The module described in the paper is a neural component able to learn the graphical features of each demotic symbol, which has been previously segmented in the images thanks to a semiautomatic procedure. A specific neural network tries to recognize the text written in the images linking the symbols segmented within the ostraka images database to the correspondent symbols available on a virtual keyboard. The graphical interface is particularly useful for teaching and research activities on this type of archaeological documentation

    Sauce criollo: una especie nativa amenazada en Patagonia

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    El sauce criollo es el único sauce nativo en Argentina. Procesos de invasión por parte de especies exóticas así como diversas actividades humanas pueden amenazar su persistencia en los ríos de Patagonia norte. Actualmente se están realizando estudios de su diversidad genética para obtener información que permita delinear planes de conservación y rescate genético.Fil: Bozzi, Jorge A.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; ArgentinaFil: Marchelli, Paula. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gallo, Leonardo A.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentin

    Vector boson production at hadron colliders: hard-collinear coefficients at the NNLO

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    We consider QCD radiative corrections to vector-boson production in hadron collisions. We present the next-to-next-to-leading order (NNLO) result of the hard-collinear coefficient function for the all-order resummation of logarithmically-enhanced contributions at small transverse momenta. The coefficient function controls NNLO contributions in resummed calculations at full next-to-next-to-leading logarithmic accuracy. The same coefficient function is used in applications of the subtraction method to perform fully-exclusive perturbative calculations up to NNLO.Comment: 13, pages, no figures. arXiv admin note: text overlap with arXiv:1106.465

    Slepton pair production in the POWHEG BOX

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    We present an implementation for slepton pair production at hadron colliders in the POWHEG BOX, a framework for combining next-to-leading order QCD calculations with parton-shower Monte-Carlo programs. Our code provides a SUSY Les Houches Accord interface for setting the supersymmetric input parameters. Decays of the sleptons and parton-shower effects are simulated with PYTHIA. Focussing on a representative point in the supersymmetric parameter space we show results for kinematic distributions that can be observed experimentally. While next-to-leading order QCD corrections are sizable for all distributions, the parton shower affects the color-neutral particles only marginally. Pronounced parton-shower effects are found for jet distributions.Comment: 10 pages, 4 figure

    The Chemokine CCL2 Mediates the Seizure-enhancing Effects of Systemic Inflammation

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    Epilepsy is a chronic disorder characterized by spontaneous recurrent seizures. Brain inflammation is increasingly recognized as a critical factor for seizure precipitation, but the molecular mediators of such proconvulsant effects are only partly understood. The chemokine CCL2 is one of the most elevated inflammatory mediators in patients with pharmacoresistent epilepsy, but its contribution to seizure generation remains unexplored. Here, we show, for the first time, a crucial role for CCL2 and its receptor CCR2 in seizure control. We imposed a systemic inflammatory challenge via lipopolysaccharide (LPS) administration in mice with mesial temporal lobe epilepsy. We found that LPS dramatically increased seizure frequency and upregulated the expression of many inflammatory proteins, including CCL2. To test the proconvulsant role of CCL2, we administered systemically either a CCL2 transcription inhibitor (bindarit) or a selective antagonist of the CCR2 receptor (RS102895). We found that interference with CCL2 signaling potently suppressed LPS-induced seizures. Intracerebral administration of anti-CCL2 antibodies also abrogated LPS-mediated seizure enhancement in chronically epileptic animals. Our results reveal that CCL2 is a key mediator in the molecular pathways that link peripheral inflammation with neuronal hyperexcitability

    Heavy-quark mass effects in Higgs boson production at the LHC

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    We study the impact of heavy-quark masses in Higgs boson production through gluon fusion at the LHC. We extend previous computations of the fully differential cross section and of the transverse momentum spectrum of the Higgs boson by taking into account the finite top- and bottom-quark masses up to O(alpha_S^3). We also discuss the issues arising when the heavy-quark mass is much smaller than the Higgs mass. Our results are implemented in updated versions of the HNNLO and HRes numerical programs.Comment: Minor modifications, results unchanged. Discussion on uncertainties added. Version published on JHE

    Scalar Particle Contribution to Higgs Production via Gluon Fusion at NLO

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    We consider the gluon fusion production cross section of a scalar Higgs boson in models where fermion and scalar massive colored particles are present. We report analytic expressions for the matrix elements of ggHggg\to Hg, qqˉHgq\bar{q}\to Hg, and qgHqqg\to Hq processes completing the calculation of the NLO QCD corrections in these extended scenarios. The formulas are written in a complete general case, allowing a flexible use for different theoretical models. Applications of our results to two different models are presented: i) a model in which the SM Higgs sector is augmented by a weak doublet scalar in the SU(Nc)SU(N_c) adjoint representation. ii) The MSSM, in the limit of neglecting the gluino contribution to the cross section.Comment: 20 pages, 5 figures. Minor changes. Refs. adde

    Vector Boson Pair Production via Vector Boson Fusion at NLO QCD

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    NLO QCD corrections to Vector Boson Pair Production via Vector Boson Fusion have recently been calculated and implemented in a parton-level Monte-Carlo program with full experimental cuts. We briefly sketch the elements of the calculation and show numerical results for the Large Hadron Collider.Comment: 6 pages, 3 figures, presented by G.Bozzi at IFAE 2007 (Napoli, April 2007) and HEP 2007 (Manchester, July 2007
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