Homyel', Belarus

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Beauchemin P.-H.,Tufts University | Bednyakov V.A.,Joint Institute for Nuclear Research | Lykasov G.I.,Joint Institute for Nuclear Research | Stepanenko Y.Yu.,Gomel State University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Assuming the possible existence of an intrinsic (or valencelike) heavy quark component in the proton distribution functions, we analyze the vector boson Z/W production, accompanied by heavy-flavor jets, in pp collisions at the LHC energies. We present theoretical predictions for differential cross sections of such processes and demonstrate their large sensitivity to parton distribution functions including an intrinsic charm component to the proton in some kinematical regions. Ratio measurements of the Z+ heavy-flavor jets differential cross sections over the corresponding spectra in W+ heavy jets events are proposed. These ratios are studied as a function of two different observables that maximize their sensitivity to the intrinsic charm component of the proton: the transverse momentum of the leading heavy-flavor jet and the longitudinal momentum fraction xFQ of this jet. Such measurements look very promising for the LHC experiments because they can supply unique information about the intrinsic charm hypothesis. © 2015 American Physical Society.

Asadchy V.S.,Aalto University | Asadchy V.S.,Gomel State University | Faniayeu I.A.,Gomel State University | Faniayeu I.A.,University of Shizuoka | And 4 more authors.
Physical Review X | Year: 2015

Energy of propagating electromagnetic waves can be fully absorbed in a thin lossy layer, but only in a narrow frequency band, as follows from the causality principle. On the other hand, it appears that there are no fundamental limitations on broadband matching of thin resonant absorbing layers. However, known thin absorbers produce significant reflections outside of the resonant absorption band. In this paper, we explore possibilities to realize a thin absorbing layer that produces no reflected waves in a very wide frequency range, while the transmission coefficient has a narrow peak of full absorption. Here we show, both theoretically and experimentally, that a thin resonant absorber, invisible in reflection in a very wide frequency range, can be realized if one and the same resonant mode of the absorbing array unit cells is utilized to create both electric and magnetic responses. We test this concept using chiral particles in each unit cell, arranged in a periodic planar racemic array, utilizing chirality coupling in each unit cell but compensating the field coupling at the macroscopic level. We prove that the concept and the proposed realization approach also can be used to create nonreflecting layers for full control of transmitted fields. Our results can have a broad range of potential applications over the entire electromagnetic spectrum including, for example, perfect ultracompact wave filters and selective multifrequency sensors.

Andreev V.V.,Gomel State University | Osland P.,University of Bergen | Pankov A.A.,Salam University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We discuss the expected sensitivity to Z′ boson effects in the W± boson pair production process at the Large Hadron Collider (LHC). The results of a model-dependent analysis of Z′ boson effects are presented as constraints on the Z-Z′ mixing angle φ and Z′ boson mass. The process pp→W+W-+X allows us to place stringent constraints on the Z-Z′ mixing angle. Specifically, we find that the present LHC bounds on the mixing angle are of the order a few times 10-3, which is of the same order as those derived from the electroweak data. These results were derived from analysis of W-pair production at s=8TeV and integrated luminosity of 20fb-1. Further improvement on the constraining of this mixing can be achieved from the analysis of data on WW→lνl′ν′ (l,l′=e or μ) and WW→lνjj final states collected at the LHC with nominal energy and luminosity, 14 TeV and 100fb-1, and should be φ∼10-4-10-3. © 2014 American Physical Society.

Andreev V.V.,Gomel State University | Pankov A.A.,Gomel State Technical University
Physics of Atomic Nuclei | Year: 2012

An analysis of effects induced by new neutral gauge Z′ bosons was performed on the basis of data from the OPAL, DELPHI, ALEPH, and L3 experiments devoted to measuring differential cross sections for the process of the annihilation production of pairs of charged gauge W± bosons at the LEP2 collider. By using these experimental data, constraints on the Z′-boson mass and on the angle of Z-Z′ mixing were obtained for a number of extended gauge models. © 2012 Pleiades Publishing, Ltd.

Asadchy V.S.,Aalto University | Asadchy V.S.,Gomel State University | Ra'Di Y.,Aalto University | Vehmas J.,Aalto University | Tretyakov S.A.,Aalto University
Physical Review Letters | Year: 2015

Conventional mirrors obey the simple reflection law that a plane wave is reflected as a plane wave, at the same angle. To engineer spatial distributions of fields reflected from a mirror, one can either shape the reflector or position some phase-correcting elements on top of a mirror surface. Here we show, both theoretically and experimentally, that full-power reflection with general control over the reflected wave phase is possible with a single-layer array of deeply subwavelength inclusions. These proposed artificial surfaces, metamirrors, provide various functions of shaped or nonuniform reflectors without utilizing any mirror. This can be achieved only if the forward and backward scattering of the inclusions in the array can be engineered independently, and we prove that it is possible using electrically and magnetically polarizable inclusions. The proposed subwavelength inclusions possess desired reflecting properties at the operational frequency band, while at other frequencies the array is practically transparent. The metamirror concept leads to a variety of applications over the entire electromagnetic spectrum, such as optically transparent focusing antennas for satellites, multifrequency reflector antennas for radio astronomy, low-profile conformal antennas for telecommunications, and nanoreflectarray antennas for integrated optics. © 2015 American Physical Society.

Dolinsky M.,Gomel State University
Olympiads in Informatics | Year: 2013

This article describes a methodology, proposed by the author, for teaching beginners to computer programming from scratch. The methodology is dedicated to teaching groups of students with various levels of knowledge and motivation. The technical base of the methodology is the distance learning system "Distance Learning Belarus", briefly DL, created by the author. © 2013 Vilnius University.

Boyarovich Yu.S.,Gomel State University
Automation and Remote Control | Year: 2012

A stationary functioning of a closed queueing network with temporarily non-active customers is analyzed. Non-active customers are located at network nodes in queues, being not serviced. For a customer, the feasibility of passing from its ordinary state to the temporarily non-active state (and backwards) is provided. Service times of customers at different nodes possess arbitrary distributions. Finally, the stationary distribution invariance of network states is established with respect to the functional form of customer service time distributions under fixed first-order moments. © Pleiades Publishing, Ltd., 2012.

Zykunov V.A.,Gomel State University
Journal of Physics: Conference Series | Year: 2014

Next-to-leading order electroweak and QCD radiative corrections to the Drell-Yan process with high dimuon masses for experiments CMS LHC at CERN have been studied in fully differential form. The FORTRAN code READY for numerical analysis of Drell-Yan observables has been presented. The radiative corrections are found to become significant for CMS LHC experiment setup. © Published under licence by IOP Publishing Ltd.

The purpose of the research was to study the invasions of plants into communities of initial stages of regenerative successions in landscapes of the southeast of Belarus (by the example of Solidago canadensis L.). Intrusion of Solidago canadensis L. into the plant succession had the following consequences: decrease in specific abundance, suppression of arboreal undergrowth, long preservation of high level of synanthropization, and inhibition of the directed changes in plant communities. © 2015, Pleiades Publishing, Ltd.

We studied the concentration and distribution of 137Cs and 90Sr in the bodies of 188 wild boar (Sus scrofa Linnaeus, 1758) taken near the Chernobyl site. Of these, 111 animals were taken in the Alienation Zone, 41 animals were taken in the Permanent Control Zone and 36 animals were taken in the Periodic Control Zone. The samples included muscle and bone (rib) tissues and samples of heart, liver, lungs, kidneys, spleen, genitals and skin. The weight of the samples was 0.5kg fresh weigh. The average concentration of 137Cs in the muscles of the wild boar found in the Alienation Zone was 46±10kBq/kg, in the Permanent Control Zone - 13±3.0kBq/kg and in the Periodic Control Zone - 0.6±0.1kBq/kg. The largest concentration of 137Cs was detected in the muscle tissue and kidneys taken animals. In some samples of muscle tissue it reached more than 660kBq/kg. The 137Cs concentrations were also high in heart and spleen up 64.3kBq/kg and 67.5kBq/kg - animals from the Alienation Zone and 10.3-10.6kBq/kg - animals from the Permanent Control zone. The lowest concentration of 137Cs was found in the lungs and skin of animals. The analyses of 90Sr concentration in the organs and tissues of the wild boar showed that 90Sr was concentrated mainly in the bone tissue. The average level of 90Sr concentration in bone was 17.6kBq/kg fresh weight animals from the Alienation Zone and 13.47 kBg/kg - animals from the Permanent Control zone. In muscle tissues and organs contained 90Sr - 30.0-110.0 Bq/kg in the Alienation Zone and 11.0-30.0 Bq/kg in the Permanent Control zone. © 2013 Elsevier Ltd.

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