3,212 research outputs found

    Measuring αs(Q2)\alpha_s(Q^2) in τ\tau Decays

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    The decay rate of the τ\tau lepton into hadrons of invariant mass smaller than QΛQCDQ\gg\Lambda_{\rm QCD} can be calculated in QCD using the OPE. Using experimental data on the hadronic mass distribution, the running coupling constant αs(Q2)\alpha_s(Q^2) is extracted in the range 0.85~\mbox{GeV}, where its value changes by about a factor~2. At Q=mτQ=m_\tau, the result is αs(mτ2)=0.33±0.03\alpha_s(m_\tau^2)=0.33\pm 0.03, corresponding to αs(mZ2)=0.119±0.004\alpha_s(m_Z^2)=0.119\pm 0.004. The running of the coupling constant is in excellent agreement with the QCD prediction based on the three-loop β\beta-function.Comment: 12 pages, 7 figures appended, to appear in the Proceedings of Les Rencontres de Physique de la Vall\'ee d'Aoste (La Thuile, Italy, March 1996), and Second Workshop on Continuous Advances in QCD (Minneapolis, Minnesota, March 1996

    Limit on the tau neutrino mass from the ALEPH experiment

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    WLCG Input to Pisa workshop on Resilience-Explicit Computing in Grids

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    This document summarizes the input from the Worldwide LHC Computing Grid (WLCG) to the workshop held on Resilience-Explicit Computing in Grids in Pisa, July 14th 2008. The techniques on which WLCG services have been built have been described in numerous papers, including [1][2][3]. They are based on many years of experience in delivering reliable services, using knowledge gained from the LEP era and from other High Energy Physics experiments around the world

    POOL File Catalog, Collection and Metadata Components

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    The POOL project is the common persistency framework for the LHC experiments to store petabytes of experiment data and metadata in a distributed and grid enabled way. POOL is a hybrid event store consisting of a data streaming layer and a relational layer. This paper describes the design of file catalog, collection and metadata components which are not part of the data streaming layer of POOL and outlines how POOL aims to provide transparent and efficient data access for a wide range of environments and use cases - ranging from a large production site down to a single disconnected laptops. The file catalog is the central POOL component translating logical data references to physical data files in a grid environment. POOL collections with their associated metadata provide an abstract way of accessing experiment data via their logical grouping into sets of related data objects.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 4 pages, 1 eps figure, PSN MOKT00

    Perturbative QCD relations inspired by hypothetical tau leptons

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    We review our recent works on tests of perturbative QCD, inspired by the relation between the hadronic decay of the tau lepton and the e+ e- annihilation into hadrons. First, we present a set of commensurate scale relations that probe the self-consistency of leading-twist QCD predictions for any observable which defines an effective charge. These tests are independent of the renormalization scheme and scale, and are applicable over wide data ranges. As an example we apply this approach to R_{e+ e-}. Second, using a differential form of these conmensurate scale relations, we present a method to measure the QCD Gell-Mann--Low Psi function.Comment: To appear in the proceedings of the QCD 99 Euroconference, 7-13th July 1999 Montpellier, France 4 pages, uses espcrc2.sty (included

    New life cycles for drosscapes: Recycle of a brownfield along the waterfront of Barcelona

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    Ponència presentada a: Session 7: Participación en planeamiento / Participation in planning. Environmental and hermeneutic plannin

    Charmed decays of the B-meson in the quark model

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    Exclusive and inclusive, semileptonic and non-leptonic, charmed decays of the B-meson are investigated in the context of a phenomenological quark model. Bound-state effects are taken care of by adopting a single (model-dependent) non-perturbative wave function, describing the motion of the light spectator quark in the B-meson. A nice reproduction of both exclusive and inclusive semileptonic data is obtained. Our predictions for the electron spectrum are presented and compared with those of the Isgur-Scora-Grinstein-Wise quark model. Finally, our approach is applied to the calculation of inclusive non-leptonic widths, obtaining a remarkable agreement with experimental findings.Comment: to appear in the Proc. of the 2^{nd} Int. Conf. on Hyperons, Charm and Beauty Hadrons, Montreal, Canada, 27-30 August 199

    Test of the Running of αs\alpha_s in τ\tau Decays

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    The τ\tau decay rate into hadrons of invariant mass smaller than s0ΛQCD\sqrt{s_0}\gg\Lambda_{\rm QCD} can be calculated in QCD assuming global quark--hadron duality. It is shown that this assumption holds for s0>0.7s_0>0.7~GeV2^2. From measurements of the hadronic mass distribution, the running coupling constant αs(s0)\alpha_s(s_0) is extracted in the range 0.7~GeV2<s0<mτ2^2<s_0<m_\tau^2. At s0=mτ2s_0=m_\tau^2, the result is αs(mτ2)=0.329±0.030\alpha_s(m_\tau^2)=0.329\pm 0.030. The running of αs\alpha_s is in good agreement with the QCD prediction.Comment: 9 pages, 3 figures appended; shortened version with new figures, to appear in Physical Review Letters (April 1996

    Junior Students’ with Hearing Impairment Psychological Correction of Learning Motivation Development

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    У статті розглянуто основні методологічні принципи, методи, етапи корекційного процесу. Обґрунтовано використання гуманістичного підходу до корекції мотиваційної сфери учіння та підібрано комплекс корекційних завдань для розвитку цієї сфери в молодших школярів із порушеннями слуху. The article presents basic methodological principles, methods, main stages of correctional process. A humanitarian approach to learning motivation development correction has been grounded and a complex of correctional tasks for junior students with hearing impairment has been selected
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