91 research outputs found

    Characteristic length scales and formation of vortices in the Abelian Higgs model in the presence of a uniform background charge

    Full text link
    In this brief report we consider a non-local Abelian Higgs model in the presence of a neutralizing uniform background charge. We show that such a system possesses vortices which key feature is a strong radial electric field. We estimate the basic properties of such an object and characteristic length scales in this model.Comment: Replaced with journal version. Some minor change

    Pseudogap state in slightly doped by aluminium and praseodymium YBa2_2Cu3_3O7δ_{7-\delta} single crystals with a given topology of plane defects

    Full text link
    In present work the conductivity in the basis plane of YBaCuO single crystals slightly doped by Al and Pr with a pre-specified topology of twin boundaries has been investigated. The excess conductivity for the analyzed samples shows dependence like Δσ(1T/T)exp(Δab/T)\Delta\sigma\sim(1-T/T^*)\exp(\Delta_{ab}^*/T) in wide temperature range Tf<T<TT_f<T<T^*, where TT^* can be represents as mean field temperature of superconducting transition. The temperature dependence of pseudogap can be satisfactory described in terms of the BCS-BEC crossover theoretical model.Comment: 3 pages, 2 figure

    Temperature Dependence of Resistivity and Current-Voltage Characteristics of the Films of Composites Based on Modified Carbon Multiwalled Nanotubes and Graphite

    Get PDF
    A film composites based on modified multiwalled carbon tubes and polymer (95/5 wt. %) Respectively on paper, without the paper by directional spinning from the liquid phase and graphite. The temperature dependence of the resistivity () in the range T 77-410 K and the corresponding current-voltage charac-teristics. Detected irreversible transitions from semiconducting to metallic conductivity in carbon nono-trubkah and a maximum at T 340 K. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3516

    Enhancement of the upper critical field by nonmagnetic impurities in dirty two-gap superconductors

    Full text link
    Quasiclassic Uzadel equations for two-band superconductors in the dirty limit with the account of both intraband and interband scattering by nonmagnetic impurities are derived for any anisotropic Fermi surface. From these equations the Ginzburg-Landau equations, and the critical temperature TcT_c are obtained. An equation for the upper critical field, which determines both the temperature dependence of Hc2(T)H_{c2}(T) and the orientational dependence of Hc2(θ)H_{c2}(\theta) as a function of the angle θ\theta between H{\bf H} and the c-axis is obtained. It is shown that the shape of the Hc2(T)H_{c2}(T) curve essentially depends on the ratio of the intraband electron diffusivities D1D_1 and D1D_1, and can be very different from the standard one-gap dirty limit theory. In particular, the value Hc2(0)H_{c2}(0) can considerably exceed 0.7TcdHc2/dTc0.7T_cdH_{c2}/dT_c, which can have important consequences for applications of MgB2MgB_2. A scaling relation is proposed which enables one to obtain the angular dependence of Hc2(θ)H_{c2}(\theta) from the equation for Hc2H_{c2} at Hc{\bf H}\| c. It is shown that, depending on the relation between D1D_1 and D2D_2, the ratio of the upper critical field Hc2/Hc2H_{c2}^\|/H_{c2}^\perp for Hab{\bf H}\| ab and Hab{\bf H}\perp ab can both increase and decrease as the temperature decreases. Implications of the obtained results for MgB2MgB_2 are discussed

    Total Cross Section Measurements with pi-, Sigma- and Protons on Nuclei and Nucleons around 600 GeV/c

    Full text link
    Total cross sections for Sigma- and pi- on beryllium, carbon, polyethylene and copper as well as total cross sections for protons on beryllium and carbon have been measured in a broad momentum range around 600GeV/c. These measurements were performed with a transmission technique adapted to the SELEX hyperon-beam experiment at Fermilab. We report on results obtained for hadron-nucleus cross sections and on results for sigma_tot(Sigma- N) and sigma_tot(pi- N), which were deduced from nuclear cross sections.Comment: 42 pages, submitted to Nucl.Phys.

    Measurement of prompt D0^{0} and D\overline{D}0^{0} meson azimuthal anisotropy and search for strong electric fields in PbPb collisions at root SNN\sqrt{S_{NN}} = 5.02 TeV

    Get PDF
    The strong Coulomb field created in ultrarelativistic heavy ion collisions is expected to produce a rapiditydependent difference (Av2) in the second Fourier coefficient of the azimuthal distribution (elliptic flow, v2) between D0 (uc) and D0 (uc) mesons. Motivated by the search for evidence of this field, the CMS detector at the LHC is used to perform the first measurement of Av2. The rapidity-averaged value is found to be (Av2) = 0.001 ? 0.001 (stat)? 0.003 (syst) in PbPb collisions at ?sNN = 5.02 TeV. In addition, the influence of the collision geometry is explored by measuring the D0 and D0mesons v2 and triangular flow coefficient (v3) as functions of rapidity, transverse momentum (pT), and event centrality (a measure of the overlap of the two Pb nuclei). A clear centrality dependence of prompt D0 meson v2 values is observed, while the v3 is largely independent of centrality. These trends are consistent with expectations of flow driven by the initial-state geometry. ? 2021 The Author. Published by Elsevier B.V. This is an open access article under the CC BY licens

    Measurement of the CP-violating phase ϕs_{s} in the B0^{0}s_{s}→J/ψ φ(1020) →μ⁺μ⁻K⁺K⁻ channel in proton-proton collisions at √s = 13 TeV

    Get PDF

    Measurement of the azimuthal anisotropy of Y(1S) and Y(2S) mesons in PbPb collisions at √S^{S}NN = 5.02 TeV

    Get PDF
    The second-order Fourier coefficients (υ2_{2}) characterizing the azimuthal distributions of Υ(1S) and Υ(2S) mesons produced in PbPb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV are studied. The Υmesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The collected data set corresponds to an integrated luminosity of 1.7 nb1^{-1}. The scalar product method is used to extract the υ2_{2} coefficients of the azimuthal distributions. Results are reported for the rapidity range |y| < 2.4, in the transverse momentum interval 0 < pT_{T} < 50 GeV/c, and in three centrality ranges of 10–30%, 30–50% and 50–90%. In contrast to the J/ψ mesons, the measured υ2_{2} values for the Υ mesons are found to be consistent with zero

    Observation of electroweak production of Wγ with two jets in proton-proton collisions at √s = 13 TeV

    Get PDF
    A first observation is presented for the electroweak production of a W boson, a photon, and two jets in proton-proton collisions. The W boson decays are selected by requiring one identified electron or muon and an imbalance in transverse momentum. The two jets are required to have a high dijet mass and a large separation in pseudorapidity. The measurement is based on data collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb1^{-1}. The observed (expected) significance for this process is 4.9 (4.6) standard deviations. After combining with previously reported CMS results at 8 TeV, the observed (expected) significance is 5.3 (4.8) standard deviations. The cross section for the electroweak Wγjj_{γjj} production in a restricted fiducial region is measured as 20.4 +/- 4.5 fb and the total cross section for Wγ_{γ} production in association with 2 jets in the same fiducial region is 108 +/- 16 fb. All results are in good agreement with recent theoretical predictions. Constraints are placed on anomalous quartic gauge couplings in terms of dimension-8 effective field theory operators
    corecore