84 research outputs found

    Strategic Priorities in Development of the Agro-Industrial Complex of the Krasnodar Region

    Get PDF
    The paper gives the agro-industrial complex characteristic of the Krasnodar Krai, analyzes the condition of its branches and defines key problems. It emphasizes such strategic development priorities of the agro-industrial complex of the Krasnodar Krai as the reclamation of land, development of the elite seed industry, intensive development of the animal industry, support of the small forms of economic management. The paper also considers the possibilities of the state support for regional agroproducers taking into account the entry of the Russian Federation in the ranks of the World Trade Organization. In compliance with that the paper offers the measures of the state regulation that is aimed to stimulation of key directions of the agrarian industry development of the region where the matter concerns a creation of the logistic basis and formation of the rural cooperation. As an example a model of the contract relations system concerning production, processing and sales of the pig-breeding products between the agricultural organizations, farm enterprises and farms of the population which can be used during the organization of productive processes both in other subsectors of the animal industry and in the branch of the plant industry. There is a conclusion that now a concentration of the state regulation on the oblique support measures for strategic development directions that is capable to provide a stimulation of "independent mechanisms" of the inner potential of the agro-industrial complex of the Krasnodar Krai. DOI: 10.5901/mjss.2015.v6n5s3p17

    Next--to--Leading Order Corrections to Meson Masses in the Heavy Quark Effective Theory

    Get PDF
    We use the QCD sum rule approach to calculate the splitting between vector and pseudoscalar mesons containing one light and one heavy quark, and the kinetic energy of the heavy quark. Our result for the splitting induced by the chromomagnetic interaction agrees to the experimental data on charm and beauty mesons. For the matrix element of the kinetic energy operator, we obtain the value K=(0.60±0.10)GeV2K=-(0.60\pm 0.10)\, {\rm GeV}^2.Comment: 33 ps., PS figures included, requires REVTEX.3 and psfig, TUM-T31-42/93/R (additional contribution to kinetic energy taken into account, marginal changes in the results

    Pion and sigma meson properties in a relativistic quark model

    Full text link
    A variety of strong and electroweak interaction properties of the pion and the light scalar sigma meson are computed in a relativistic quark model. Under the assumption that the resulting coupling of these mesons to the constituent quarks is identical, the sigma meson mass is determined as M_sigma=385.4 MeV. We discuss in detail the gauging of the non-local meson-quark interaction and calculate the electromagnetic form factor of the pion and the form factors of the pi(0) -> gamma gamma and sigma -> gamma gamma processes. We obtain explicit expressions for the relevant form factors and evaluate the leading and next-to-leading orders for large Euclidean photon virtualities. Turning to the decay properties of the sigma we determine the width of the electromagnetic sigma -> gamma gamma transition and discuss the strong decay sigma -> pi pi. In a final step we compute the nonleptonic decays D -> sigma pi and B -> sigma pi relevant for the possible observation of the sigma meson. All our results are compared to available experimental data and to results of other theoretical studies.Comment: 46 page

    Hadronic τ\tau decay, the renormalization group, analiticity of the polarization operators and QCD parameters

    Full text link
    The ALEPH data on hadronic tau-decay is throughly analysed in the framework of QCD. The perturbative calculations are performed in 1-4-loop approximation. The analytical properties of the polarization operators are used in the whole complex q^2 plane. It is shown that the QCD prediction for R_{tau} agrees with the measured value R_{tau} not only for conventional Lambda^{conv}_3 = (618+-29) MeV but as well as for Lambda^{new}_3 = (1666+-7) MeV. The polarization operator calculated using the renormgroup has nonphysical cut [-Lambda^2_3, 0]. If Lambda_3 = Lambda^{conv}_3, the contribution of only physical cut is deficient in the explanation of the ALEPH experiment. If Lambda_3 = Lambda^{new}_3 the contribution of nonphysical cut is very small and only the physical cut explains the ALEPH experiment. The new sum rules which follow only from analytical properties of polarization operators are obtained. Basing on the sum rules obtained, it is shown that there is an essential disagreement between QCD perturbation theory and the tau-lepton hadronic decay experiment at conventional value Lambda_3. In the evolution upwards to larger energies the matching of r(q^2) (Eq.(12)) at the masses J/psi, Upsilon and 2m_t was performed. The obtained value alpha_s(-m^2_z) = 0.141+-0.004 (at Lambda_3 = Lambda^{new}_3) differs essentially from conventional value, but the calculation of the values R(s) = sigma(e+e- -> hadrons)/sigma(e+e- -> mu+mu-), R_l = Gamma(Z -> hadrons)/Gamma(Z -> leptons), alpha_s(-3 GeV^2), alpha_s(-2.5 GeV^2) does not contradict the experiments.Comment: 20 page

    Radiative Correction to the Dirichlet Casimir Energy for λϕ4\lambda\phi^{4} Theory in Two Spatial Dimensions

    Get PDF
    In this paper, we calculate the next to the leading order Casimir energy for real massive and massless scalar fields within λϕ4\lambda\phi^{4} theory, confined between two parallel plates with the Dirichlet boundary condition in two spatial dimensions. Our results are finite in both cases, in sharp contrast to the infinite result reported previously for the massless case. In this paper we use a renormalization procedure introduced earlier, which naturally incorporates the boundary conditions. As a result our radiative correction term is different from the previously calculated value. We further use a regularization procedure which help us to obtain the finite results without resorting to any analytic continuation techniques.Comment: 8 pages, 3 figure

    Exclusive Radiative B-Decays in the Light-Cone QCD Sum Rule Approach

    Get PDF
    We carry out a detailed study of exclusive radiative rare BB-decays in the framework of the QCD sum rules on the light cone, which combines the traditional QCD sum rule technique with the description of final state vector mesons in terms of the light-cone wave functions of increasing twist. The decays considered are: Bu,dK+γ,Bu,dρ+γ,Bdω+γB_{u,d} \to K^* +\gamma, B_{u,d}\to \rho+\gamma, B_d\to \omega+\gamma and the corresponding decays of the BsB_s mesons, Bsϕ+γB_s\to \phi+\gamma and BsK+γB_s\to K^*+\gamma. Based on our estimate of the transition form factor F_1^{B \to K^*\pg}(0) =0.32\pm0.05, we find for the branching ratio BR(BK+γ)=(4.8±1.5)×105BR(B \to K^* + \gamma) = (4.8\pm 1.5)\times 10^{-5}, which is in agreement with the observed value measured by the CLEO collaboration. We present detailed estimates for the ratios of the radiative decay form factors, which are then used to predict the rates for the exclusive radiative B-decays listed above. This in principle allows the extraction of the CKM matrix element Vtd|V_{td}| from the penguin-dominated CKM-suppressed radiative decays when they are measured. We give a detailed discussion of the dependence of the form factors on the bb-quark mass and on the momentum transfer, as well as their interrelation with the CKM-suppressed semileptonic decay form factors in Bρ++νB\to \rho+\ell+\nu, which we also calculate in our approach.Comment: 32 pages, 10 uuencoded figures, LaTeX, preprint CERN-TH 7118/9

    Mass spectra of doubly heavy Omega_QQ' baryons

    Full text link
    We evaluate the masses of baryons composed of two heavy quarks and a strange quark with account for spin-dependent splittings in the framework of potential model with the KKO potential motivated by QCD with a three-loop beta-function for the effective charge consistent with both the perturbative limit at short distances and linear confinement term at long distances between the quarks. The factorization of dynamics is supposed and explored in the nonrelativistic Schroedinger equation for the motion in the system of two heavy quarks constituting the doubly heavy diquark and the strange quark interaction with the diquark. The limits of approach, its justification and uncertainties are discussed. Excited quasistable states are classified by the quantum numbers of heavy diquark composed by the heavy quarks of the same flavor.Comment: 14 pages, revtex4-file, 3 eps-figures, 5 tables, typos correcte

    Strong Couplings of Heavy Mesons to A Light Vector Meson in QCD

    Get PDF
    We make a detailed analysis of the BBρ(DDρ)BB\rho(DD\rho) and BBρ(DDρ)B^*B\rho(D^{*}D\rho) strong couplings gBBρ(gDDρ)g_{BB\rho}(g_{DD\rho}) and gBBρ(gDDρ)g_{B^*B\rho}(g_{D^{*}D\rho}) using QCD light cone sum rules(LCSR). The existing some negligence is pointed out in the previous LCSR calculation on gBBρ(gDDρg_{B^*B\rho} (g_{D^{\ast}D\rho}) and an updated estimate is presented. Our findings can be used to understand the behavior of the B,DρB,D \to \rho semileptonic form factors at large momentum transitions.Comment: 15 pages, latex, 2 figures, version appearing in PRD, typos correcte

    Analysis of the vector form factors fKπ+(Q2)f^+_{K\pi}(Q^2) and fKπ(Q2)f^-_{K\pi}(Q^2) with light-cone QCD sum rules

    Get PDF
    In this article, we calculate the vector form factors fKπ+(Q2)f^+_{K\pi}(Q^2) and fKπ(Q2)f^-_{K\pi}(Q^2) within the framework of the light-cone QCD sum rules approach. The numerical values of the fKπ+(Q2)f^+_{K\pi}(Q^2) are compatible with the existing theoretical calculations, the central value of the fKπ+(0)f^+_{K\pi}(0), fKπ+(0)=0.97f^+_{K\pi}(0)=0.97, is in excellent agreement with the values from the chiral perturbation theory and lattice QCD. The values of the fKπ(0)|f^-_{K\pi}(0)| are very large comparing with the theoretical calculations and experimental data, and can not give any reliable predictions. At large momentum transfers with Q2>5GeV2Q^2> 5GeV^2, the form factors fKπ+(Q2)f^+_{K\pi}(Q^2) and fKπ(Q2)|f^-_{K\pi}(Q^2)| can either take up the asymptotic behavior of 1Q2\frac{1}{Q^2} or decrease more quickly than 1Q2\frac{1}{Q^2}, more experimental data are needed to select the ideal sum rules.Comment: 22 pages, 16 figures, revised version, to appear in Eur. Phys. J.

    DDπD^*D\pi and BBπB^*B\pi couplings in QCD

    Get PDF
    We calculate the DDπD^*D\pi and BBπB^*B\pi couplings using QCD sum rules on the light-cone. In this approach, the large-distance dynamics is incorporated in a set of pion wave functions. We take into account two-particle and three-particle wave functions of twist 2, 3 and 4. The resulting values of the coupling constants are gDDπ=12.5±1g_{D^*D\pi}= 12.5\pm 1 and gBBπ=29±3g_{B^*B\pi}= 29\pm 3 . From this we predict the partial width \Gamma (D^{*+} \ra D^0 \pi^+ )=32 \pm 5~ keV . We also discuss the soft-pion limit of the sum rules which is equivalent to the external axial field approach employed in earlier calculations. Furthermore, using gBBπg_{B^*B\pi} and gDDπg_{D^*D\pi} the pole dominance model for the B \ra \pi and D\ra \pi semileptonic form factors is compared with the direct calculation of these form factors in the same framework of light-cone sum rules.Comment: 27 pages (LATEX) +3 figures enclosed as .uu file MPI-PhT/94-62 , CEBAF-TH-94-22, LMU 15/9
    corecore