The Confinement Property in SU(3) Gauge Theory

We study confinement property of pure SU(3) gauge theory, combining in this effort the non-perturbative gluon and ghost propagators obtained as solutions of Dyson--Schwinger equations with solutions of an integral ladder diagram summation type equation for the Wilson loop. We obtain the string potential and effective UV coupling.Comment: 7 pages, 7 figures, v2: references added, discussion reorganize

Is the ground state of Yang-Mills theory Coulombic?

We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-abelian Coulomb fields is found to have a good overlap with the ground state for all charge separations. In fact, the overlap increases as the lattice regulator is removed. This opens up the possibility that the Coulomb state is the true ground state in the continuum limit.Comment: 10 pages, 9 .eps figure

The atomic structure of large-angle grain boundaries Σ5\Sigma 5 and Σ13\Sigma 13 in YBa2Cu3O7−δ{\rm YBa_2Cu_3O_{7-\delta}} and their transport properties

We present the results of a computer simulation of the atomic structures of large-angle symmetrical tilt grain boundaries (GBs) $\Sigma 5$ (misorientation angles \q{36.87}{^{\circ}} and \q{53.13}{^{\circ}}), $\Sigma 13$ (misorientation angles \q{22.62}{^{\circ}} and \q{67.38}{^{\circ}}). The critical strain level $\epsilon_{crit}$ criterion (phenomenological criterion) of Chisholm and Pennycook is applied to the computer simulation data to estimate the thickness of the nonsuperconducting layer ${\rm h_n}$ enveloping the grain boundaries. The ${\rm h_n}$ is estimated also by a bond-valence-sum analysis. We propose that the phenomenological criterion is caused by the change of the bond lengths and valence of atoms in the GB structure on the atomic level. The macro- and micro- approaches become consistent if the $\epsilon_{crit}$ is greater than in earlier papers. It is predicted that the symmetrical tilt GB $\Sigma5$ \theta = \q{53.13}{^{\circ}} should demonstrate a largest critical current across the boundary.Comment: 10 pages, 2 figure

Fluctuations of the baryonic flux-tube junction from effective string theory

In quenched QCD, where the dynamic creation of quark-antiquark pairs out of the vacuum is neglected, a confined baryonic system composed of three static quarks exhibits string-like behaviour at large interquark separation, with the formation of flux tubes characterized by the geometry of the so-called Y ansatz. We study the fluctuations of the junction of the three flux tubes, assuming the dynamics to be governed by an effective bosonic string model. We show that the asymptotic behaviour of the effective width of the junction grows logarithmically with the distance between the sources, with the coefficient depending on the number of joining strings, on the dimension of spacetime and on the string tension.Comment: 9 pages, 2 figures, RevTeX4 style, revision: style changed, references added, more explanations added, typos correcte

Effect of 3d-doping on the electronic structure of BaFe2As2

The electronic structure of BaFe2As2 doped with Co, Ni, and Cu has been studied by a variety of experimental and theoretical methods, but a clear picture of the dopant 3d states has not yet emerged. Herein we provide experimental evidence of the distribution of Co, Ni, and Cu 3d states in the valence band. We conclude that the Co and Ni 3d states provide additional free carriers to the Fermi level, while the Cu 3d states are found at the bottom of the valence band in a localized 3d10 shell. These findings help shed light on why superconductivity can occur in BaFe2As2 doped with Co and Ni but not Cu.Comment: 18 pages, 8 figure

The Analysis of Injuries and Mortality Risks Level as a Result of Road Accident in Regions of the Central and Eastern Europe

In the article the analysis of the frequency, traumatism and mortality of road accidents has been carried out at the regional level for the countries of Central and Eastern Europe and has made it possible to draw conclusions regarding certain spatial features of the distribution of these indicators and on the nonrandom nature of the location of their values on maps of the CEE regions featured in the study. On the basis of methods of spatial statistics and econometrics we have demonstrated the existence of a spatial structure in the distribution of the risks and consequences of road accidents in the various regions. Cluster analysis has enabled us to distinguish uniform clusters of regions categorised by the risks, traumatism and mortality rates of road accidents. Based on an analysis of these indicators we have introduced the evaluation of an integrated safety level for regions of the countries of Central and Eastern Europe. This allows us to estimate the complex influence of the risks and their consequences road accidents on the level of safety for certain regions or groups of regions. The results of the research which has been conducted can be used for the improvement of national and regional programs of road and transport safety, and for the development of strategies and actions aimed at reducing the risks and consequences of road accidents in certain regions

Phenotypic traits differentiating the genetic resources of pea (<i>Pisum sativum</i> L.) by the type of use

The paper presents an analysis of the data obtained for pea accessions from the VIR collection studied at the Adler Experiment Station in the setting of the Krasnodar Territory in 2017–2019. It was for the first time that these accessions were studied for a set of phenotypic traits. The object of the study was a sample of 494 pea accessions originated from 43 countries and 18 regions and territories of the Russian Federation. The work was carried out in compliance with the methodological guidelines developed at VIR. Statistica 13.3 software was employed for statistical data processing. An assessment of four qualitative, 10 quantitative and four phenological traits in the accessions made it possible to differentiate them by the type of use, that is, as dry, forage and garden peas. The varieties differing in the type of use significantly differed by the values of such traits as stem length, number of pods per plant, number of nodes to the first flower, number of flowers in the inflorescence, the maximum number of seeds per pod, pod length, and a narrower pod of forage pea compared to that of dry and garden peas. The average values of these traits were recorded for the peas with different types of use. The maximum difference was noted between garden and forage pea varieties. Dry pea varieties occupied an intermediate position. The complex of phenotypic traits identified determines the differences between three types of pea use, which is important when selecting the initial material for breeding appropriate varieties

INFLUENCE OF DOSES AND RELATIONSHIP BASED ON ON YIELDAND QUALITY OF GRAIN WHEAT

The results of research of influence of long-term application of different doses and ratios of fertilizers on podzolized chernozem in field crop rotation in the conditions of the Right Bank Forest-steppe Ukraine on the yield and quality of winter wheat, the predecessor of which was soybean. It was determined that due to different doses, ratios and types of fertilizers it is possible to increase the yield of culture by 31–96 %. The highest quality indicators ensured the use of mineral fertilizers with a dose of N150P30K40 per 1 ha of crop rotation – 13,5 % protein and 28,4 % gluten (group A 2 of the class of quality group). With the increase of doses of phosphorus and potassium fertilizers twice the content of protein and gluten has not significantly increased. It that in areas where fertilizers were not introduced, the grain corresponded to the 6th grade, only nitric fertilizers with a dose of N150 and their application on the phosphoric-potassium background ensured the production of grain of grade 2 quality. It was established that the density of the connection due to the correlation coefficient between the weight of 1000 grains and the grain was weak (r = 0,19), but between the weight of 1000 grains and the yield – moderate (r = 0,41), between the content of protein and gluten – strong (r = 0,76). According to a generalized quality indicator, winter wheat grain of the best quality was formed in the experiment variant with the introduction of N150P60K40, and on average per 1 ha of field crop rotation – N110P60K40

Physics at BES-III

This physics book provides detailed discussions on important topics in $\tau$-charm physics that will be explored during the next few years at \bes3 . Both theoretical and experimental issues are covered, including extensive reviews of recent theoretical developments and experimental techniques. Among the subjects covered are: innovations in Partial Wave Analysis (PWA), theoretical and experimental techniques for Dalitz-plot analyses, analysis tools to extract absolute branching fractions and measurements of decay constants, form factors, and CP-violation and \DzDzb-oscillation parameters. Programs of QCD studies and near-threshold tau-lepton physics measurements are also discussed.Comment: Edited by Kuang-Ta Chao and Yi-Fang Wan

Two-Fermion Production in Electron-Positron Collisions

This report summarizes the results of the two-fermion working group of the LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the theoretical calculations of the two fermion production process in the electron-positron collision at LEP2 center of the mass energies are reported. The Bhabha process and the production of muon, tau, neutrino and quark pairs is covered. On the basis of comparison of various calculations, theoretical uncertainties are estimated and compared with those needed for the final LEP2 data analysis. The subjects for the further studies are identified.Comment: 2-fermion working group report of the LEP2 Monte Carlo Workshop 1999/2000, 113 pages, 24 figures, 35 table