61,393 research outputs found

    Cosmic rays from multiwavelength observations of the Galactic diffuse emission

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    Cosmic rays (CRs) generate diffuse emission while interacting with the Galactic magnetic field (B-field), the interstellar gas and the radiation field. This diffuse emission extends from radio, microwaves, through X-rays, to high-energy gamma rays. Diffuse emission has considerably increased the interest of the astrophysical community due to recent detailed observations by Planck, Fermi-LAT, and by very-high-energy Cherenkov telescopes. Observations of this emission and comparison with detailed predictions are used to gain information on the properties of CRs, such as their density, spectra, distribution and propagation in the Galaxy. Unfortunately disentangling and characterizing this diffuse emission strongly depends on uncertainties in the knowledge of unresolved sources, gas, radiation fields, and B-fields, other than CRs throughout the Galaxy. We report here on recent multiwavelength observations of the Galactic diffuse emission, and discuss the diffuse emission produced by CRs and its model uncertainties, comparing observations with predictions. The importance for forthcoming telescopes, especially for the Square Kilometre Array Telescope (SKA) and the Cherenkov Telescope Array (CTA), and for future missions at MeV energies is also addressed.Comment: Proceedings of the TAUP 2015 - XIV International Conference on Topics in Astroparticle and Underground Physics, September 2015 Torino, Ital

    QCD results from ATLAS

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    The most recent QCD measurements performed in ATLAS are reviewed; the results summarized here are based on data collected with the ATLAS detector during the 2010 and 2011 data taking in proton-proton collisions at center of mass energy sqrt s = 7 TeV at the Large Hadron Collider, corresponding approximately to an integrated luminosity of 36 pb^-1 and 4.6 fb^-1 respectively.Comment: 10 pages, Workshop on high energy physics in the near future, Rio De Janeiro, Brazil, 17 - 24 Mar 201

    A stringy perspective on the quantum integrable model/gauge correspondence

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    We present a string theory realization for the correspondence between quantum integrable models and supersymmetric gauge theories. The quantization results from summing the effects of fundamental strings winding around a compact direction. We discuss the examples of the XXZ gauge/Bethe correspondence and five-dimensional \Omega--deformed SYM on M x S^1

    Schwarzschild Spacetime without Coordinates

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    We discuss how to construct the full Schwarzschild (Kruskal-Szekeres) spacetime in one swoop by using the bundle of orthonormal Lorentz frames and the Einstein equation without the use of coordinates. We never have to write down the Kruskal-Szekeres or an equivalent form of the metric.Comment: 36 pages, 4 figures; some typos corrected, a few paragraphs added for clarificatio

    Verlinde bundles of families of hypersurfaces and their jumping lines

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    Verlinde bundles are vector bundles VkV_k arising as the direct image π(Lk)\pi_*(\mathcal L^{\otimes k}) of polarizations of a proper family of schemes π ⁣:XS\pi\colon \mathfrak X \to S. We study the splitting behavior of Verlinde bundles in the case where π\pi is the universal family XO(d)\mathfrak X \to |\mathcal O(d)| of hypersurfaces of degree dd in Pn\mathbb P^n and calculate the cohomology class of the locus of jumping lines of the Verlinde bundles Vd+1V_{d+1} in the cases n=2,3n=2,3.Comment: This version adds a missing definition in Prop. 2.2 and corrects minor typo

    Axion-dilaton cosmology, Ricci flows and integrable structures

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    In this work we study renormalization-group flows by deforming a class of conformal sigma-models. At leading order in α\alpha', renormalization-group equations represent a Ricci flow. In the three-sphere background, the latter is described by the Halphen system, which is exactly solvable in terms of modular forms. The round sphere is found to be the unique perturbative infra-red fixed point at one loop order.Comment: 2 pages, based on a talk given at the Cargese Summer School, May 22 to June 3, 200

    A two-dimensional non-equilibrium dynamic model

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    This paper develops a non-equilibrium dynamic model (NEDyM) with Keynesian features (it allows for a disequilibrium between output and demand and it considers a constant marginal propensity to consume), but where production is undertaken under plain neoclassical conditions (a constant returns to scale production function, with the stocks of capital and labor fully employed, is assumed). The model involves only two endogenous / prognostic variables: the stock of physical capital per unit of labor and a goods inventory measure. The two-dimensional system allows for a careful analysis of local and global dynamics. Points of bifurcation and long-term cyclical motion are identified. The main conclusion is that the disequilibrium hypothesis leads to persistent fluctuations generated by intrinsic deterministic factors
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