1,514 research outputs found

    Transverse Enhancement Model and MiniBooNE Charge Current Quasi-Elastic Neutrino Scattering Data

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    Recently proposed Transverse Enhancement Model of nuclear effects in Charge Current Quasi-Elastic neutrino scattering [A. Bodek, H. S. Budd, and M. E. Christy, Eur. Phys. J. C{\bf 71} (2011) 1726] is confronted with the MiniBooNE high statistics experimental data. It is shown that the {\it effective} large axial mass model leads to better agreement with the data.Comment: 4 pages, 6 figure

    The Effect of Large Amplitude Fluctuations in the Ginzburg-Landau Phase Transition

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    The lattice Ginzburg-Landau model in d=3 and d=2 is simulated, for different values of the coherence length ξ\xi in units of the lattice spacing aa, using a Monte Carlo method. The energy, specific heat, vortex density vv, helicity modulus Γμ\Gamma_\mu and mean square amplitude are measured to map the phase diagram on the plane TξT-\xi. When amplitude fluctuations, controlled by the parameter ξ\xi, become large (ξ1\xi \sim 1) a proliferation of vortex excitations occurs changing the phase transition from continuous to first order.Comment: 4 pages, 5 postscript (eps) figure

    Manual de la Micro, Pequeña y Mediana Empresa. Una contribución a la mejora de los sistemas de información y el desarrollo de las políticas públicas

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    Niet Leids onderzoek van medewerkers FG

    Coherent States and N Dimensional Coordinate Noncommutativity

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    Considering coordinates as operators whose measured values are expectations between generalized coherent states based on the group SO(N,1) leads to coordinate noncommutativity together with full NN dimensional rotation invariance. Through the introduction of a gauge potential this theory can additionally be made invariant under NN dimensional translations. Fluctuations in coordinate measurements are determined by two scales. For small distances these fluctuations are fixed at the noncommutativity parameter while for larger distances they are proportional to the distance itself divided by a {\em very} large number. Limits on this number will lbe available from LIGO measurements.Comment: 16 pqges. LaTeX with JHEP.cl

    Delta-isobar relativistic meson exchange currents in quasielastic electron scattering

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    We study the role of the Δ\Delta-isobar current on the response functions for high energy inclusive quasielastic electron scattering from nuclei. We consider a general Lagrangian which is compatible with contact invariance and perform a fully relativistic calculation in first-order perturbation theory for one-particle emission. The dependence of the responses upon off-shell parametrizations is analyzed and found to be mild. A discussion of scaling behaviour and a comparison with various non-relativistic approaches are also presented.Comment: 26 pages, 9 figures; one page of text added; corrected errors in eq

    Relativistic pionic effects in quasielastic electron scattering

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    The impact of relativistic pionic correlations and meson-exchange currents on the response functions for electromagnetic quasielastic electron scattering from nuclei is studied in detail. Results in first-order perturbation theory are obtained for one-particle emission electronuclear reactions within the context of the relativistic Fermi gas model. Improving upon previous analyses where non-relativistic reductions of the currents were performed, here a fully relativistic analysis in which both forces and currents are treated consistently is presented. Lorentz covariance is shown to play a crucial role in enforcing the gauge invariance of the theory. Effects stemming uniquely from relativity in the pionic correlations are identified and, in particular, a comprehensive study of the self-energy contributions and of the currents associated with the pion is presented. First- and second-kind scaling for high momentum transfer is investigated.Comment: 43 pages, 21 figure

    Reionization: Characteristic Scales, Topology and Observability

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    Recently the numerical simulations of the process of reionization of the universe at z>6 have made a qualitative leap forward, reaching sufficient sizes and dynamic range to determine the characteristic scales of this process. This allowed making the first realistic predictions for a variety of observational signatures. We discuss recent results from large-scale radiative transfer and structure formation simulations on the observability of high-redshift Ly-alpha sources. We also briefly discuss the dependence of the characteristic scales and topology of the ionized and neutral patches on the reionization parameters.Comment: 4 pages, 5 figures (4 in color), to appear in Astronomy and Space Science special issue "Space Astronomy: The UV window to the Universe", proceedings of 1st NUVA Conference ``Space Astronomy: The UV window to the Universe'' in El Escorial (Spain

    Niemann-Pick disease type-B: a unique case report with compound heterozygosity and complicated lipid management

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    BACKGROUND: Niemann-Pick disease (NPD) is a rare autosomal recessive hereditary disease characterized by deficient activity of acid sphingomyelinase. CASE PRESENTATION: We present a case of NPD type B with a unique compound heterozygosity for SMPD1 (NM_000543.4:c.[84delC];[96G¿>¿A]) in which both mutations that induce an early stop codon are located before the second in-frame initiation codon. The clinical presentation of the patient is compatible with NPD type B. She was initially diagnosed of Gaucher Disease, but her altered lipid profile led to a clinical suspicion of NPD. Combined high doses of atorvastatin and ezetimibe were given to treat the severe hypercholesterolemia. CONCLUSIONS: The pharmacological management of the lipid profile in these patients is important. A unique compound mutation in SMPD1 gene is described

    Topcolor-Assisted Supersymmetry

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    It has been known that the supersymmetric flavor changing neutral current problem can be avoided if the squarks take the following mass pattern, namely the first two generations with the same chirality are degenerate with masses around the weak scale, while the third generation is very heavy. We realize this scenario through the supersymmetric extension of a topcolor model with gauge mediated supersymmetry breaking.Comment: 12 pages, latex, no figure

    Kontsevich product and gauge invariance

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    We analyze the question of U(1)U_{\star} (1) gauge invariance in a flat non-commutative space where the parameter of non-commutativity, θμν(x)\theta^{\mu\nu} (x), is a local function satisfying Jacobi identity (and thereby leading to an associative Kontsevich product). We show that in this case, both gauge transformations as well as the definitions of covariant derivatives have to modify so as to have a gauge invariant action. We work out the gauge invariant actions for the matter fields in the fundamental and the adjoint representations up to order θ2\theta^{2} while we discuss the gauge invariant Maxwell theory up to order θ\theta. We show that despite the modifications in the gauge transformations, the covariant derivative and the field strength, Seiberg-Witten map continues to hold for this theory. In this theory, translations do not form a subgroup of the gauge transformations (unlike in the case when θμν\theta^{\mu\nu} is a constant) which is reflected in the stress tensor not being conserved.Comment: 7 page
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