2,306 research outputs found

    Central pseudoscalar production in pp scattering and the gluon contribution to the proton spin

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    Central pseudoscalar production in pppp scattering is suppressed at small values of QQ_\perp, where QQ is defined as the difference between the momenta transferred from the two protons. Such a behaviour is expected if the production occurs through the fusion of two vectors. Photon exchange could provide the dominant contribution at low transferred momenta, but we argue that an extension of the experiment could probe the gluon contribution to the proton spin.Comment: 12 pages, 2 figures and 3 tables, uses epsf.sty. Added references and tables. Minor changes include

    Thermal Performance of the Supporting System for the Large Hadron Collider (LHC) Superconducting Magnets

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    The LHC collider will be composed of approximately 1700 main ring superconducting magnets cooled to 1.9 K in pressurised superfluid helium and supported within their cryostats on low heat in-leak column-type supports. The precise positioning of the heavy magnets and the stringent thermal budgets imposed by the machine cryogenic system, require a sound thermo-mechanical design of the support system. Each support is composed of a main tubular thin-walled structure in glass-fibre reinforced epoxy resin, with its top part interfaced to the magnet at 1.9 K and its bottom part mounted onto the cryostat vacuum vessel at 293 K. In order to reduce the conduction heat in-leak at 1.9 K, each support mounts two heat intercepts at intermediate locations on the column, both actively cooled by cryogenic lines carrying helium gas at 4.5-10 K and 50-65 K. The need to assess the thermal performance of the supports has lead to setting up a dedicated test set-up for precision heat load measurements on prototype supports. This paper presents the thermal design of the support system of the LHC arc magnets. The results of the thermal tests of a prototype support made in industry are illustrated and discussed. A mathematical model has been set up and refined by the comparison with test results, with the scope of extrapolating the observed thermal performance to different geometrical and material parameters. Finally, the calculated estimate of the heat load budgets of the support system and their contribution to the total cryogenic budget for an LHC arc are presented

    The GRAAL high resolution BGO calorimeter and its energy calibration and monitoring system

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    We describe the electromagnetic calorimeter built for the GRAAL apparatus at the ESRF. Its monitoring system is presented in detail. Results from tests and the performance obtained during the first GRAAL experiments are given. The energy calibration accuracy and stability reached is a small fraction of the intrinsic detector resolution.Comment: 19 pages, 14 figures, submitted to Nuclear Instruments and Method

    Phenomenological evidence for the energy dependence of the ηη\eta-\eta' mixing angle

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    A phenomenological analysis on various decay processes is performed using an energy-dependent ηη\eta-\eta' mixing angle scheme. Special attention is given to the radiative couplings between lowest-lying vector and pseudoscalar mesons. The agreement between our predictions and the experimental values is remarkable. This analysis opens a connection to two-angle fits in the ηη\eta-\eta' sector.Comment: 13 pages. Introduction slightly modified. A second Table added. Conclusions remain unchange

    Aspirin Recapitulates Features of Caloric Restriction

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    G.K. is supported by the Ligue contre le Cancer Comitede Charente-Maritime (equipe labelisee); Agence National de la Recherche (ANR) - Projets blancs; ANR under the frame of E-Rare-2, the ERA-Net for Research on Rare Diseases; Association pour la recherche sur le cancer (ARC); Canceropole Ile-de-France; Chancelerie des universites de Paris (Legs Poix), Fondation pour la Recherche Medicale (FRM); a donation by Elior; the European Commission (ArtForce); the European Research Council (ERC; ERC-2012-AdG-320339-Immunodeath); Fondation Carrefour; Institut National du Cancer (INCa); INSERM (HTE); Institut Universitaire de France; LeDucq Foundation; the LabEx Immuno-Oncology; the RHU Torino Lumiere; the Searave Foundation; the SIRIC Stratified Oncology Cell DNA Repair and Tumor Immune Elimination (SOCRATE); the SIRIC Cancer Research and Personalized Medicine (CARPEM); and the Paris Alliance of Cancer Research Institutes (PACRI). F.M. is grateful to the FWF for grants LIPOTOX, P 29262, P 27893, P 29203, and P24381-B20 and the BMWFW for grants "Unconventional research" and "Flysleep (80.109/0001 -WF/V/3b/2015). G.M. is funded by the Ramon y Cajal Program (RYC-2013-12751) and supported by Spain's Ministerio de Economia y Competitividad (BFU2015-68539) and the BBVA Foundation (SV-15-FBBVA-2). Some nematode strains used in this work were provided by the Caenorhabditis Genetic Center (CGC) at the University of Minnesota, which is funded by NIH Office of Research Infrastructure Programs (P40 OD010440).Pietrocola, F., Castoldi, F., Markaki, M., Lachkar, S., Chen, G., Enot, D.P., Durand, S., Bossut, N., Tong, M., Malik, S.A., Loos, F., Dupont, N., Mariño, G., Abdelkader, N., Madeo, F., Maiuri, M.C., Kroemer, R., Codogno, P., Sadoshima, J., Tavernarakis, N., Kroemer, G

    Efeito do dano mecânico na qualidade fisiológica e na capacidade de expansão de sementes de milho pipoca.

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    Com o objetivo de dar subsidio aos produtores de sementes e/ou graos de milho pipoca, para melhorar a qualidade fisiologica da producao, sementes da cultivar CMS-43 foram submetidas a tres niveis de danificacao mecanica (sem danos, com danos e com danos dobrados), e avaliadas pelos testes de germinacao, vigor (condutividade eletrica) e capacidade de expansao. Os resultados demonstraram que sementes danificadas reduzem significativamente a germinacao, o vigor e a capacidade de expansao das sementes. Concluiu-se que indiferente a finalidade da producao, sementes e/ou graos, a colheita do milho pipoca precisa ser feita com o minimo de danificacao mecanica possivel, para propiciar um produto com maxima qualidade

    Two loop results from one loop computations and non perturbative solutions of exact evolution equations

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    A nonperturbative method is proposed for the approximative solution of the exact evolution equation which describes the scale dependence of the effective average action. It consists of a combination of exact evolution equations for independent couplings with renormalization group improved one loop expressions of secondary couplings. Our method is illustrated by an example: We compute the beta-function of the quartic coupling lambda of an O(N) symmetric scalar field theory to order lambda^3 as well as the anomalous dimension to order lambda^2 using only one loop expressions and find agreement with the two loop perturbation theory. We also treat the case of very strong coupling and confirm the existence of a "triviality bound".Comment: 32 pages, HD-THEP-94-3, replaced because: lines too long, blank line

    Integrated Safety and Environment Group: Annual Report 2003

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    This report summarizes the main activities of the Integrated Safety and Environment (IE) Group of the Safety Commission (TIS) during the year 2003, and the results obtained. The different topics in which the group is active are covered: environment, quality management, safety training and major accidents follow-up

    Possible fabrication techniques and welding specifications for the external cylinder of the CMS coil

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    The Compact Muon Solenoid (CMS) is one of the experiments, which are being designed in the framework of the Large Hadron Collider (LHC) project at CERN. The design field of the CMS magnet is 4 T, the magnetic length is 12.5 m and the free aperture is 6 m in diameter. This is achieved with a 4 layer and 5 module superconducting Al- stabilized coil energized at a nominal current of 20 kA at 4.5 K. In the CMS coil the structural function is ensured, unlike in other existing Al-stabilized thin solenoids, both by the Al-alloy reinforced conductor and the external cylinder. The calculated stress level in the cylinder at operating conditions is particularly severe. In this paper the different possible fabrication techniques are assessed and compared and a possible welding specification for this component is given. (9 refs)
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