1,318 research outputs found

    Confinement and scaling in deep inelastic scattering

    Full text link
    We show that parton confinement in the final state generates large 1/Q21/Q^2 corrections to Bjorken scaling, thus leaving less room for the logarithmic corrections. In particular, the xx-scaling violations at large xx are entirely described in terms of power corrections. For treatment of these non-perturbative effects, we derive a new expansion in powers of 1/Q21/Q^2 for the structure function that is free of infra-red singularities and which reduces corrections to the leading term. The leading term represents scattering from an off-mass-shell parton, which keeps the same virtual mass in the final state. It is found that this quasi-free term is a function of a new variable xˉ\bar x, which coincides with the Bjorken variable xx for Q2Q^2\to\infty. The two variables are very different, however, at finite Q2Q^2. In particular, the variable xˉ\bar x depends on the invariant mass of the spectator particles. Analysis of the data at large xx shows excellent scaling in the variable xˉ\bar x, and determines the value of the diquark mass to be close to zero. xˉ\bar x-scaling allows us to extract the structure function near the elastic threshold. It is found to behave as F2(1x)3.7F_2\sim (1-x)^{3.7}. Predictions for the structure functions based on xˉ\bar x-scaling are made.Comment: Discussion of target mass corrections is added. Accepted for publication in Phys. Rev.

    Polarization Correlometry of Birefringence Images of Human Blood Layers

    Get PDF
    To analyze the coordinate-like structure of Stokes-parametric and Mueller-matrix images of optically anisotropic components of biological tissues, the two-point polarization-correlational approach was applied. On this basis parameters the method of cross-correlational definition of parameters (average sizes, asymmetry factor) of correlational contour was developed, which defines the topographical structure of the characteristic meanings of Stokes-parametric and Mueller-matrix images of histological sections of biological tissues

    Distortion in a 7xxx aluminum alloy during liquid phase sintering

    Get PDF
    The distortion in a sintered 7xxx aluminum alloy, Al-7Zn-2.5Mg-1Cu (wt. pct), has been investigated by sintering three rectangular bars in each batch at 893 K (620 °C) for 0 to 40 minutes in nitrogen, followed by air or furnace cooling. They were placed parallel to each other, equally spaced apart at 2 mm, with their long axes being perpendicular to the incoming nitrogen flow. Pore evolution in each sample during isothermal sintering was examined metallographically. The compositional changes across sample mid-cross section and surface layers were analyzed using energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy depth profiling, respectively. The two outer samples bent toward the middle one, while the middle sample was essentially distortion free after sintering. The distortion in the outer samples was a result of differential shrinkage between their outer and inner surfaces during isothermal sintering. The porous outer surface showed an enrichment of oxygen around the large pores as well as lower magnesium and zinc contents than the interior and inner surface of the same sample, while the inner surface was distinguished by the presence of AlN. The differential shrinkage was caused by different oxygen contents in local sintering atmosphere and unbalanced loss of magnesium and zinc between the outer and inner surfaces

    Growth and properties of ferromagnetic In(1-x)Mn(x)Sb alloys

    Full text link
    We discuss a new narrow-gap ferromagnetic (FM) semiconductor alloy, In(1-x)Mn(x)Sb, and its growth by low-temperature molecular-beam epitaxy. The magnetic properties were investigated by direct magnetization measurements, electrical transport, magnetic circular dichroism, and the magneto-optical Kerr effect. These data clearly indicate that In(1-x)Mn(x)Sb possesses all the attributes of a system with carrier-mediated FM interactions, including well-defined hysteresis loops, a cusp in the temperature dependence of the resistivity, strong negative magnetoresistance, and a large anomalous Hall effect. The Curie temperatures in samples investigated thus far range up to 8.5 K, which are consistent with a mean-field-theory simulation of the carrier-induced ferromagnetism based on the 8-band effective band-orbital method.Comment: Invited talk at 11th International Conference on Narrow Gap Semiconductors, Buffalo, New York, U.S.A., June 16 - 20, 200

    Surface structure and solidification morphology of aluminum nanoclusters

    Full text link
    Classical molecular dynamics simulation with embedded atom method potential had been performed to investigate the surface structure and solidification morphology of aluminum nanoclusters Aln (n = 256, 604, 1220 and 2048). It is found that Al cluster surfaces are comprised of (111) and (001) crystal planes. (110) crystal plane is not found on Al cluster surfaces in our simulation. On the surfaces of smaller Al clusters (n = 256 and 604), (111) crystal planes are dominant. On larger Al clusters (n = 1220 and 2048), (111) planes are still dominant but (001) planes can not be neglected. Atomic density on cluster (111)/(001) surface is smaller/larger than the corresponding value on bulk surface. Computational analysis on total surface area and surface energies indicates that the total surface energy of an ideal Al nanocluster has the minimum value when (001) planes occupy 25% of the total surface area. We predict that a melted Al cluster will be a truncated octahedron after equilibrium solidification.Comment: 22 pages, 6 figures, 34 reference

    Quasiparticles as composite objects in the RVB superconductor

    Full text link
    We study the nature of the superconducting state, the origin of d-wave pairing, and elementary excitations of a resonating valence bond (RVB) superconductor. We show that the phase string formulation of the t-J model leads to confinement of bare spinon and holon excitations in the superconducting state, though the vacuum is described by the RVB state. Nodal quasiparticles are obtained as composite excitations of spinon and holon excitations. The d-wave pairing symmetry is shown to arise from short range antiferromagnetic correlations

    Nonconstant electronic density of states tunneling inversion for A15 superconductors: Nb3Sn

    Full text link
    We re-examine the tunneling data on A15 superconductors by performing a generalized McMillan-Rowell tunneling inversion that incorporates a nonconstant electronic density of states obtained from band-structure calculations. For Nb3Sn, we find that the fit to the experimental data can be slightly improved by taking into account the sharp structure in the density of states, but it is likely that such an analysis alone is not enough to completely explain the superconducting tunneling characteristics of this material. Nevertheless, the extracted Eliashberg function displays a number of features expected to be present for the highest quality Nb3Sn samples.Comment: 11 pages, 11 figure

    The spin and charge gaps of the half-filled N-leg Kondo ladders

    Full text link
    In this work, we study N-leg Kondo ladders at half-filling through the density matrix renormalization group. We found non-zero spin and charge gaps for any finite number of legs and Kondo coupling J>0J>0. We also show evidence of the existence of a quantum critical point in the two dimensional Kondo lattice model, in agreement with previous works. Based on the binding energy of two holes, we did not find evidence of superconductivity in the 2D Kondo lattice model close to half-filling.Comment: 4 pages, 1 table, 3 fig

    On the stability of standing matter waves in a trap

    Get PDF
    We discuss excited Bose-condensed states and find the criterion of dynamical stability of a kink-wise state, i.e., a standing matter wave with one nodal plane perpendicular to the axis of a cylindrical trap. The dynamical stability requires a strong radial confinement corresponding to the radial frequency larger than the mean-field interparticle interaction. We address the question of thermodynamic instability related to the presence of excitations with negative energy.Comment: 4 pages, 3 figure

    The Effects of Shopping Well-Being and Shopping Ill-Being on Consumer Life Satisfaction

    Get PDF
    Individuals hold two distinct sets of beliefs about shopping activities: Positive beliefs regarding the degree to which shopping contributes to quality of life (shopping well-being), and negative beliefs related to the degree to which shopping activities result in overspending time, effort, and money (shopping ill-being). Shopping well-being and shopping ill-being are conceptualized as independent constructs in that shopping ill-being is not treated as negative polar of a single dimension. That is, one can experience both shopping well-being as well as shopping ill-being, simultaneously. We hypothesized that (1) shopping well-being is a positive predictor of life satisfaction, (2) shopping ill-being is a negative predictor of life satisfaction, and (3) shopping well-being does contribute to life satisfaction under conditions of low than high shopping ill-being. The study surveyed 1035 respondents in the UK. The study results supported hypotheses 1 and 3, not Hypothesis 2. The paper discusses the implications of these findings for retailers, macro-marketers, and policy makers. © 2017 Springer Science+Business Media Dordrecht and The International Society for Quality-of-Life Studies (ISQOLS
    corecore