135 research outputs found

    Rho-meson form factors and QCD sum rules

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    We present predictions for rho-meson form factors obtained from the analysis of QCD sum rules in next-to-leading order of perturbation theory. The radiative corrections turn out to be sizeable and should be taken into account in rigorous theoretical analysis.Comment: LaTeX file, 14 pages, 7 figure

    Langmuir wave linear evolution in inhomogeneous nonstationary anisotropic plasma

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    Equations describing the linear evolution of a non-dissipative Langmuir wave in inhomogeneous nonstationary anisotropic plasma without magnetic field are derived in the geometrical optics approximation. A continuity equation is obtained for the wave action density, and the conditions for the action conservation are formulated. In homogeneous plasma, the wave field E universally scales with the electron density N as E ~ N^{3/4}, whereas the wavevector evolution varies depending on the wave geometry

    Prophylaxis of Acute Enteric Infections and Viral Hepatitis A under Emergency Situation in the Territory of the Amur Region

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    Hydrological natural disasters and post-flooding epidemiological situation are often attended by epidemic emergencies creating a threat to life-comforts sustaining and sanitary-epidemiologic welfare of a significant number of citizens. To evaluate the efficiency of preventive and anti-epidemic measures the analysis of acute enteric infection incidence rate in the Amur Region for the past decade, during the high water and in the post-flooding period in 2013 has been carried out. Displayed are the data concerning the prophylaxis of acute enteric infections and viral hepatitis A under the conditions of the emergency situation caused by natural calamities notably by flood in the Amur Region. Adequate planning and operative implementation of organizational, preventive and anti-epidemic measures have made it possible to control acute enteric and viral hepatitis A infection at the sporadic level

    Идентификация погрешностей интегрированной системы ориентации и навигации с помощью нейросетевых алгоритмов

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    Показана можливість підвищення точності, достовірності та надійності визначення місцезнаходження та орієнтації рухомого об’єкта в реальному часі за рахунок використання нейромережевих алгоритмів в обчислювачі інтегрованої БІНС/СНС системи орієнтації та навігації.It is shown in a paper the possibility of increasing of accuracy and reliability of determination of coordinates and attitude of moving object in real time by the help of using of neuronet algorithms in processor of the integrated SINS/SNS attitude and navigation system.Показана возможность повышения точности, достоверности и надежности определения местоположения и ориентации подвижного объекта в реальном времени за счет использование нейросетевых алгоритмов в вычислителе интегрированной БИНС/СНС системы ориентации и навигации

    Two-particle decays of B_c meson into charmonium states

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    The factorization of hard and soft contributions into the hadronic decays of B_c meson at large recoils is explored in order to evaluate the decay rates into the S, P and D-wave charmonia associated with rho and pi. The constraints of approach applicability and uncertainties of numerical estimates are discussed. The mode with the J/psi in the final state is evaluated taking into account the cascade radiative electromagnetic decays of excited P-wave states, that enlarges the branching ratio by 20-25%.Comment: 13 pages, LaTeX axodraw-style, 1 figure, 2 table

    Integrability and Transcendentality

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    We derive the two-loop Bethe ansatz for the sl(2) twist operator sector of N=4 gauge theory directly from the field theory. We then analyze a recently proposed perturbative asymptotic all-loop Bethe ansatz in the limit of large spacetime spin at large but finite twist, and find a novel all-loop scaling function. This function obeys the Kotikov-Lipatov transcendentality principle and does not depend on the twist. Under the assumption that one may extrapolate back to leading twist, our result yields an all-loop prediction for the large-spin anomalous dimensions of twist-two operators. The latter also appears as an undetermined function in a recent conjecture of Bern, Dixon and Smirnov for the all-loop structure of the maximally helicity violating (MHV) n-point gluon amplitudes of N=4 gauge theory. This potentially establishes a direct link between the worldsheet and the spacetime S-matrix approach. A further assumption for the validity of our prediction is that perturbative BMN (Berenstein-Maldacena-Nastase) scaling does not break down at four loops, or beyond. We also discuss how the result gets modified if BMN scaling does break down. Finally, we show that our result qualitatively agrees at strong coupling with a prediction of string theory.Comment: 45 pages LaTeX, 3 postscript figures. v2: Chapter on BMN scaling and transcendentality added. v3: version accepted for publication in JSTA

    Proceedings of the third French-Ukrainian workshop on the instrumentation developments for HEP

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    The reports collected in these proceedings have been presented in the third French-Ukrainian workshop on the instrumentation developments for high-energy physics held at LAL, Orsay on October 15-16. The workshop was conducted in the scope of the IDEATE International Associated Laboratory (LIA). Joint developments between French and Ukrainian laboratories and universities as well as new proposals have been discussed. The main topics of the papers presented in the Proceedings are developments for accelerator and beam monitoring, detector developments, joint developments for large-scale high-energy and astroparticle physics projects, medical applications.Comment: 3rd French-Ukrainian workshop on the instrumentation developments for High Energy Physics, October 15-16, 2015, LAL, Orsay, France, 94 page

    Mass Bounds on a Very Light Neutralino

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    Within the Minimal Supersymmetric Standard Model (MSSM) we systematically investigate the bounds on the mass of the lightest neutralino. We allow for non-universal gaugino masses and thus even consider massless neutralinos, while assuming in general that R-parity is conserved. Our main focus are laboratory constraints. We consider collider data, precision observables, and also rare meson decays to very light neutralinos. We then discuss the astrophysical and cosmological implications. We find that a massless neutralino is allowed by all existing experimental data and astrophysical and cosmological observations.Comment: 36 pages, 13 figures, minor modification in astro-physical bounds. EPJC versio

    Retrospective Analysis of Enterovirus Infection Morbidity Rate in the Territory of the Amur Region and Peculiarities of Epidemic Process in the Period of Large-Scale Flood

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    There has been observed a tendency to increment of enterovirus morbidity rate over the past seven years. Foci of this infection have been formed in the area from time to time, with minor forms of the disease being predominant in clinical findings. Genetically enteroviruses circulating in the Amur Region have been characterized as homogenous; however there is a genetic relation among them with and, consequently, epidemiologic connection to enteroviruses originated from China. However, since May, 2013 there has been detected a boost activation of epidemic process as regards enteroviral infection, followed by the formation of two major foci with clustered infection, due to importation from Thailand as well. Emergency situation under conditions of flood (August-September, 2013) has contributed to aggravation of epidemiological situation on enteroviral infection. It has led to the increase in numbers of the exposed up to the maximum level for the past few years. In the territory of the temporal accommodation sites, where affected by high water and exposed to the infection population was placed, registered have been the cases of clustered enterovirus infection
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