3,107 research outputs found

    Heavy quarkonium production in the Regge limit of QCD: from Tevatron to LHC

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    Heavy quarkonium production in the framework of the non-relativistic quantum chromodynamics and leading order of the parton Reggeization approach at the Tevatron and LHC is discussed. In this note, we compare our predictions for the bottomonium production at the LHC due to the color-singlet approximation of the non-relativistic quantum chromodynamics with CMS and LHCb data. It is found, that in the production of Upsilon(1S) states, the color-singlet mechanism is dominating, whereas to describe the data for the inclusive Upsilon(2S) and Upsilon(3S) production, the color- octet contributions should be taken into account.Comment: 4 pages, 1 figure, Xth Quark Confinement and the Hadron Spectrum 8-12 October 2012 TUM Campus Garching, Munich, German

    ψ(2S)\psi(2S) and Υ(3S)\Upsilon(3S) hadroproduction in the parton Reggeization approach: Yield, polarization, and the role of fragmentation

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    The hadroproduction of the radially excited heavy-quarkonium states ψ(2S)\psi(2S) and Υ(3S)\Upsilon(3S) at high energies is studied in the parton reggeization approach and the factorization formalism of nonrelativistic QCD at lowest order in the strong-coupling constant αs\alpha_s and the relative heavy-quark velocity vv. A satisfactory description of the ψ(2S)\psi(2S) transverse-momentum (pTp_T) distributions measured by ATLAS, CMS, and LHCb at center-of-mass energy S=7\sqrt{S}=7 TeV is obtained using the color-octet long-distance matrix elements (LDMEs) extracted from CDF data at S=1.96\sqrt{S}=1.96 TeV. The importance of the fragmentation mechanism and the scale evolution of the fragmentation functions in the upper pTp_T range, beyond 30 GeV, is demonstrated. The Υ(3S)\Upsilon(3S) pTp_T distributions measured by CDF at S=1.8\sqrt{S}=1.8 TeV and by LHCb at S=7\sqrt{S}=7 TeV and forward rapidities are well described using LDMEs fitted to ATLAS data at S=7\sqrt{S}=7 TeV. Comparisons of polarization measurements by CDF and CMS at large pTp_T values with our predictions consolidate the familiar problem in the ψ(2S)\psi(2S) case, but yield reasonable agreement in the Υ(3S)\Upsilon(3S) case.Comment: 28 pages, 12 figures, minor text additions, references added, matches journal versio

    Hyperbolic carbon nanoforest for phase matching of ordinary and backward electromagnetic waves: second harmonic generation

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    We show that deliberately engineered dispersive metamaterial slab can enable the co-existence and phase matching of contra-propagating ordinary fundamental and extraordinary backward second harmonic surface electromagnetic modes. Energy flux and phase velocity are contra-directed in the backward waves which is the phenomenon that gives rise to unique nonlinear optical propagation processes. We show that frequencies, phase, and group velocities, as well as nanowaveguide losses inherent to the electromagnetic modes supported by such metamaterial, can be tailored to maximize conversion of frequencies and to reverse propagation direction of the generated wave. Such a possibility, which is of paramount importance for nonlinear photonics, is proved with a numerical model of the hyperbolic metamaterial made of carbon nanotubes standing on the metal surface. Extraordinary properties of the backward-wave second harmonic generation in the reflection direction and of the corresponding frequency doubling metareflector in the THz are investigated with a focus on the pulsed regime.Comment: 6 pages, 5 figures. arXiv admin note: text overlap with arXiv:1602.0249

    Pharmacological Correction of Neurological Disorders in Case of Multiple Sclerosis

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    The article analyzes the possibility of drug correction of common neurological disorders (pain, anxiety, depression, insomnia) using antidepressants under the conditions of experimental equivalent of multiple sclerosis on the background of basic drug therapy with methylprednisolone.Assessment of antidepressants antinociceptive potential identified “a range of activity” of the mentioned medicines (analgesic activity of classical amitriptyline antidepressant was accepted as conventional unit): paroxetine (0.9 c.u.), amitriptyline (1 c.u.), fluoxetine (1.11 c.u.) and trittico (1.16 c.u.).Comparative analysis of the duration of animals’ fading in the water at the forced swimming (Porsolt forced swimming test) found that the ability to weaken the level of anxiety and concern was the most significant for trittico and paroxetine groups. Immobilization time was 1.7 (p£0.05) and 1.6 (p£0.05), respectively, which was shorter than the corresponding figures of the active control group. The effect of antidepressants on latency, sleep duration when administered on a background of basic drug therapy with methylprednisolone was characterized by the following indicators: trittico (-66.5% and + 133.45%)³fluoxetine (-60.5% and + 117.79%)³paroxetine (-61.8% and + 93.59%)³amitriptyline (-52.75% and + 81.85%).Thus, trittico and paroxetine were reasonable to administer under the experimental equivalent of multiple sclerosis taking into account the basic hormonal therapy as a means of drug correction of pain, anxiety, depression and sleep disorders

    Solving the difference initial-boundary value problems by the operator exponential method

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    We suggest a modification of the operator exponential method for the numerical solving the difference linear initial boundary value problems. The scheme is based on the representation of the difference operator for given boundary conditions as the perturbation of the same operator for periodic ones. We analyze the error, stability and efficiency of the scheme for a model example of the one-dimensional operator of second difference
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