256 research outputs found

    Calculation of the Membrane Thickness of Magnetite Nanoparticles on the Surface of the Transparent Conductive Electrode in the Electric Field

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    We observe and study the reflection and interference in the two-layer thin film composed of a conductive layer of ITO and dispersed particles of magnetic fluid (magnetite). In an electric field the equivalent thickness of the membrane is increased by varying the thickness of the second layer. At a certain value of the electric field the layer becomes unstable, its thickness varies periodically, autowave process leading to the characteristic active centers (pacemakers), spiral waves (reverberators) was observed

    Calculation of the Membrane Thickness of Magnetite Nanoparticles on the Surface of the Transparent Conductive Electrode in the Electric Field

    Get PDF
    We observe and study the reflection and interference in the two-layer thin film composed of a conductive layer of ITO and dispersed particles of magnetic fluid (magnetite). In an electric field the equivalent thickness of the membrane is increased by varying the thickness of the second layer. At a certain value of the electric field the layer becomes unstable, its thickness varies periodically, autowave process leading to the characteristic active centers (pacemakers), spiral waves (reverberators) was observed

    Thickness Calculation of Thin Transparent Conductive Membrane on the Border with a Magnetic Fluid

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    The determination method of the membrane thickness of ITO (InSnO2). The magnetite nanoparticles in the electric field migrate, forming the thin layer near conductive ITO membrane with varying thickness. Lighting this structure by monochromatic plane polarized light the interference of light in the thin membrane was observed. The experimental values of the intensity of the reflected light from the surface of «ITO – layer of magnetite particles" for samples with different thickness of the conductive coating

    Jets in Deep Inelastic Scattering and High Energy Photoproduction at HERA

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    Recent results on jet production in neutral current deep inelastic scattering and high energy photoproduction at the HERA electron-proton-collider are briefly reviewed. The results are compared to QCD expectations in NLO and αs\alpha_s determinations using these data are summarized.Comment: 12 pages, 10 figures, talk given at the 9th Adriatic Meeting "Particle Physics and the Universe" in Dubrovnik/Croatia, 4.-24.9.200

    Thickness Calculation of Thin Transparent Conductive Membrane on the Border with a Magnetic Fluid

    Get PDF
    The determination method of the membrane thickness of ITO (InSnO2). The magnetite nanoparticles in the electric field migrate, forming the thin layer near conductive ITO membrane with varying thickness. Lighting this structure by monochromatic plane polarized light the interference of light in the thin membrane was observed. The experimental values of the intensity of the reflected light from the surface of «ITO – layer of magnetite particles" for samples with different thickness of the conductive coating

    Bose-Einstein Correlations and Color Reconnection in W-pair production

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    We propose a systematic study of Bose-Einstein correlations between identical hadrons coming from different W decays. Experimentally accessible signatures of these correlations as well as of possible color reconnection effects are discussed on the basis of two-particle inclusive densities.Comment: 24 pages, 9 eps figures, submitted to Eur. J. Phys.

    Expanding running coupling effects in the hard Pomeron

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    We study QCD hard processes at scales of order k^2 > Lambda^2 in the limit in which the beta-function coefficient - b is taken to be small, but alphas(k) is kept fixed. The (nonperturbative) Pomeron is exponentially suppressed in this limit, making it possible to define purely perturbative high-energy Green's functions. The hard Pomeron exponent acquires diffusion and running coupling corrections which can be expanded in the b parameter and turn out to be dependent on the effective coupling b alphas^2 Y. We provide a general setup for this b-expansion and we calculate the first few terms both analytically and numerically.Comment: 36 pages, 15 figures, additional references adde

    Next-to-leading BFKL phenomenology of forward-jet cross sections at HERA

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    We show that the forward-jet measurements performed at HERA allow for a detailed study of corrections due to next-to-leading logarithms (NLL) in the Balitsky-Fadin-Kuraev-Lipatov (BFKL) approach. While the description of the d\sigma/dx data shows small sensitivity to NLL-BFKL corrections, these can be tested by the triple differential cross section d\sigma/dxdk_T^2dQ^2 recently measured. These data can be successfully described using a renormalization-group improved NLL kernel while the standard next-to-leading-order QCD or leading-logarithm BFKL approaches fail to describe the same data in the whole kinematic range. We present a detailed analysis of the NLL scheme and renormalization-scale dependences and also discuss the photon impact factors.Comment: 15 pages, 9 figures, new title, NLL-BFKL saddle-point approximation replaced by exact integratio

    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

    Towards Jetography

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    As the LHC prepares to start taking data, this review is intended to provide a QCD theorist's understanding and views on jet finding at hadron colliders, including recent developments. My hope is that it will serve both as a primer for the newcomer to jets and as a quick reference for those with some experience of the subject. It is devoted to the questions of how one defines jets, how jets relate to partons, and to the emerging subject of how best to use jets at the LHC.Comment: 95 pages, 28 figures, an extended version of lectures given at the CTEQ/MCNET school, Debrecen, Hungary, August 2008; v2 includes additional discussion in several places, as well as other clarifications and additional references
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