461 research outputs found

    Formación del modelo óptimo del cluster industrial de empresas de confección chinas basado en la gestión de la zona económica estratégica

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    El artículo analiza el mecanismo para desarrollar un modelo óptimo de un clúster industrial asociado con la formación de zonas económicas estratégicas utilizando el ejemplo de las empresas textiles chinas. se está resolviendo el problema de determinar el conjunto óptimo de zonas económicas estratégicas prometedoras para maximizar los ingresos de las ventas de productos de clúster industrial en un conjunto dado de zonas económicas estratégicas. se determina la condición de la empresa, que se corresponde más estrechamente con las necesidades del mercado en cuanto al volumen y la variedad de productos de acuerdo con la composición y capacidad de las áreas estratégicas de negocios. se está buscando una política de inversión e innovación que asegure la transformación evolutiva de la arquitectura empresarial de acuerdo con la visión del estado actual y basada en minimizar las inversiones atraídas. se investigan el enfoque de clúster y la integración vertical, lo que puede proporcionar una ventaja competitiva sostenible para las empresas de la industria ligera durante muchos años. se propone y prueba un modelo original para crear un grupo industrial en el ejemplo de las empresas de costura en china

    Entropy Analysis in \pi^{+}\rp and \rK^{+}\rp Collisions at s=22\sqrt{s}=22 GeV

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    The entropy properties are analyzed by Ma's coincidence method in \pi^{+}\rp and \rK^{+}\rp collisions of the NA22 experiment at 250 GeV/cc incident momentum. By using the R\'{e}nyi entropies, we test the scaling law and additivity properties in rapidity space. The behavior of the R\'{e}nyi entropies as a function of the average number of particles is investigated. The results are compared with those from the {\sc Pythia} Monte Carlo event generator.Comment: LaTeX, 11 pages, 5 figure to be appeared in Acta Phys. Pol.

    Direct J/Psi hadroproduction in k_\perp-factorization and the color octet mechanism

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    The hadroproduction of direct J/Psi in the framework of the k_\perp-factorization approach is studied. The color-singlet contribution is essentially larger than in the collinear approach but is still an order of magnitude below the data. The deficit may be well described by the color octet contribution with the value of the matrix element substantially decreased in comparison with the fits in the collinear factorization. This should lead to a reduction of the large transverse polarization, predicted in the collinear approach.Comment: 3 pages, LaTeX, 2 eps figures, final PRD versio

    Sum rules and dualities for generalized parton distributions: is there a holographic principle?

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    To leading order approximation, the physical content of generalized parton distributions (GPDs) that is accessible in deep virtual electroproduction of photons or mesons is contained in their value on the cross-over trajectory. This trajectory separates the t-channel and s-channel dominated GPD regions. The underlying Lorentz covariance implies correspondence between these two regions through their relation to GPDs on the cross-over trajectory. This point of view leads to a family of GPD sum rules which are a quark analogue of finite energy sum rules and it guides us to a new phenomenological GPD concept. As an example, we discuss the constraints from the JLab/Hall A data on the dominant u-quark GPD H. The question arises whether GPDs are governed by some kind of holographic principle.Comment: 45 pages, 4 figures, Sect. 2 reorganized for clarity. Typos in Eq. (20) corrected. 4 new refs. Matches published versio

    J/psi plus jet associated production in two-photon collisions at next-to-leading order

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    We calculate the cross section of J/psi plus jet inclusive production in gamma gamma collisions at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD) focusing on direct photoproduction. Apart from direct J/psi production, we also include the feed-down from directly-produced chi_{cJ} and psi' mesons. We discuss the analytical calculation, in particular the treatment of the various types of singularities and the NRQCD operator renormalization, in some detail. We present theoretical predictions for the future e^+e^- linear collider TESLA, taking into account both brems- and beamstrahlung.Comment: 43 pages, 11 figure

    Heavy Quark Fragmentation Functions for D-wave Quarkonium and Charmed Beauty Mesons

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    At the large transverse momentum region, the production of heavy-heavy bound-states such as charmonium, bottomonium, and bˉc\bar bc mesons in high energy e+ee^+e^- and hadronic collisions is dominated by parton fragmentation. We calculate the heavy quark fragmentation functions into the D-wave quarkonium and bˉc\bar bc mesons to leading order in the strong coupling constant and in the non-relativistic expansion. In the bˉc\bar b c meson case, one set of its D-wave states is expected to lie below the open flavor threshold. The total fragmentation probability for a bˉ\bar b antiquark to split into the D-wave bˉc\bar b c mesons is about 2×1052 \times 10^{-5}, which implies that only 2\% of the total pseudo-scalar ground state BcB_c comes from the cascades of these orbitally excited states.Comment: 26 pages in RevteX and 3 figures in postscript. Also available at http://www.ph.utexas.edu/~cheung/paper.htm

    Heavy quarkonium: progress, puzzles, and opportunities

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    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the BB-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

    Critical Correlations of Wilson Lines in SU(3) and the High Energy γp\gamma^*p Cross Section

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    We discuss deep inelastic scattering at high energies as a critical phenomenon in 2+1 space - time dimensions. In the limit of Bjorken x0x \to 0, QCDQCD SU(3) with quark fields becomes a critical theory with a diverging correlation length ξ(x)x12λ2\xi(x) \propto x^{-\frac{1}{2 \lambda_2}} where the exponent λ2=2.52\lambda_2=2.52 is obtained from the center group Z(3) of SU(3). We conjecture that the dipole wave function of the virtual photon for transverse sizes 1/Q<x<ξ1/Q<x_{\bot}<\xi obeys correlation scaling Ψ(x)(1+n)\Psi \propto (x_{\bot})^{-(1+n)} before exponentially decaying for distances larger than the correlation length. Using this behavior combined with different xx -independent dipole proton cross sections we calculate the proton structure function and compare with the experimental data. We take the good agreement with the measured proton structure function F2(x,Q2)_2(x,Q^2) as an indication that at high energies dimensional reduction to an effective three dimensional theory with a critical point occurs.Comment: 21 pages, 3 figure

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter
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