67,390 research outputs found

    Higgs and new physics at high energy

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    The observation of a new particle in the search for the Standard Model (SM) Higgs boson at the LHC, reported by the ATLAS and CMS collaborations, is a milestone in the quest to understand electroweak symmetry breaking. The evidence at the level of 5 σ\sigma for a Higgs boson-like particle has been published by both experiments after a preliminary analysis of the data from the LHC Run-I. Precision measurements of the new particle are of critical importance. This document reviews the mass and spin measurement, the couplings scale factor measurements and the limits on new physics derived from these results.Comment: Presented at the 2014 Flavor Physics and CP Violation (FPCP-2014), Marseille, France, May 26-30 2014, 9 pages, 9 figure

    Stretched exponential relaxation in the Coulomb glass

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    The relaxation of the specific heat and the entropy to their equilibrium values is investigated numerically for the three-dimensional Coulomb glass at very low temperatures. The long time relaxation follows a stretched exponential function, f(t)=f0exp[(t/τ)β]f(t)=f_0\exp[-(t/\tau)^\beta], with the exponent β\beta increasing with the temperature. The relaxation time follows an Arrhenius behavior divergence when T0T\to 0. A relation between the specific heat and the entropy in the long time regime is found.Comment: 5 pages and 4 figure

    Measuring the transition to homogeneity with photometric redshift surveys

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    We study the possibility of detecting the transition to homogeneity using photometric redshift catalogs. Our method is based on measuring the fractality of the projected galaxy distribution, using angular distances, and relies only on observable quantites. It thus provides a way to test the Cosmological Principle in a model-independent unbiased way. We have tested our method on different synthetic inhomogeneous catalogs, and shown that it is capable of discriminating some fractal models with relatively large fractal dimensions, in spite of the loss of information due to the radial projection. We have also studied the influence of the redshift bin width, photometric redshift errors, bias, non-linear clustering, and surveyed area, on the angular homogeneity index H2 ({\theta}) in a {\Lambda}CDM cosmology. The level to which an upcoming galaxy survey will be able to constrain the transition to homogeneity will depend mainly on the total surveyed area and the compactness of the surveyed region. In particular, a Dark Energy Survey (DES)-like survey should be able to easily discriminate certain fractal models with fractal dimensions as large as D2 = 2.95. We believe that this method will have relevant applications for upcoming large photometric redshift surveys, such as DES or the Large Synoptic Survey Telescope (LSST).Comment: 14 pages, 14 figure

    Effect of Non Gaussian Noises on the Stochastic Resonance-Like Phenomenon in Gated Traps

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    We exploit a simple one-dimensional trapping model introduced before, prompted by the problem of ion current across a biological membrane. The voltage-sensitive channels are open or closed depending on the value taken by an external potential that has two contributions: a deterministic periodic and a stochastic one. Here we assume that the noise source is colored and non Gaussian, with a qq-dependent probability distribution (where qq is a parameter indicating the departure from Gaussianity). We analyze the behavior of the oscillation amplitude as a function of both qq and the noise correlation time. The main result is that in addition to the resonant-like maximum as a function of the noise intensity, there is a new resonant maximum as a function of the parameter qq.Comment: Communication to LAWNP01, Proceedings to be published in Physica D, RevTex, 8 pgs, 5 figure
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