135 research outputs found
Rho-meson form factors and QCD sum rules
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
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
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
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
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
Gold-plated Mode of CP-Violation in Decays of B_c Meson from QCD Sum Rules
The model-independent method based on the triangle ideology is implemented to
extract the CKM-matrix angle gamma in the decays of doubly heavy long-lived
meson B_c. We analyze a color structure of diagrams and conditions to
reconstruct two reference-triangles by tagging the flavor and CP eigenstates of
D^0 meson in the fixed exclusive channels. The characteristic branching ratios
are evaluated in the framework of QCD sum rules.Comment: 11 pages, RevTeX4 file, 4 eps-figure
Integrability and Transcendentality
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
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
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
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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