7,129 research outputs found

    The Muon Anomalous Magnetic Moment in the Reduced Minimal 3-3-1 Model

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    We study the muon anomalous magnetic moment (g2)μ(g-2)_{\mu} in the context of the reduced minimal 3-3-1 model recently proposed in the literature. In particular, its spectrum contains a doubly charged scalar (H±±H^{\pm \pm}) and gauge boson (U±±U^{\pm \pm}), new singly charged vectors (V±V^{\pm}) and a ZZ^{\prime} boson, each of which might give a sizeable contribution to the (g2)μ(g-2)_{\mu}. We compute the 1-loop contributions from all these new particles to the (g2)μ(g-2)_{\mu}. We conclude that the doubly charged vector boson provides the dominant contribution, and by comparing our results with the experimental constraints we derive an expected value for the scale of SU(3)LU(1)NSU(3)_L\otimes U(1)_N symmetry breaking vχ2v_{\chi} \sim 2 TeV. We also note that, if the discrepancy in the anomalous moment is resolved in the future without this model then the constraints will tighten to requiring vχ>2.7v_\chi > 2.7 TeV with current precision, and will entirely rule out the model if the expected precision is achieved by the future experiment at Fermilab.Comment: 19 pages, 4 figure

    The MIPSGAL View of Supernova Remnants in the Galactic Plane

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    We report the detection of Galactic supernova remnants (SNRs) in the mid-infrared (at 24 and 70 μm), in the coordinate ranges 10° < l < 65° and 285° < l < 350°, |b| < 1°, using MIPS aboard the Spitzer Space Telescope. We search for infrared counterparts to SNRs in Green's catalog and identify 39 out of 121, i.e., a detection rate of about 32%. Such a relatively low detection fraction is mainly due to confusion with nearby foreground/background sources and diffuse emission. The SNRs in our sample show a linear trend in [F_8/F_(24)] versus [F_(70)/F_(24)]. We compare their infrared fluxes with their corresponding radio flux at 1.4 GHz and find that most remnants have a ratio of 70 μm to 1.4 GHz which is similar to those found in previous studies of SNRs (with the exception of a few that have ratios closer to those of H II regions). Furthermore, we retrieve a slope close to unity when correlating infrared (24 and 70 μm) with 1.4 GHz emission. Our survey is more successful in detecting remnants with bright X-ray emission, which we find is well correlated with the 24 μm morphology. Moreover, by comparing the power emitted in the X-ray, infrared, and radio, we conclude that the energy released in the infrared is comparable to the cooling in the X-ray range

    Suppression of Anderson localization of light and Brewster anomalies in disordered superlattices containing a dispersive metamaterial

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    Light propagation through 1D disordered structures composed of alternating layers, with random thicknesses, of air and a dispersive metamaterial is theoretically investigated. Both normal and oblique incidences are considered. By means of numerical simulations and an analytical theory, we have established that Anderson localization of light may be suppressed: (i) in the long wavelength limit, for a finite angle of incidence which depends on the parameters of the dispersive metamaterial; (ii) for isolated frequencies and for specific angles of incidence, corresponding to Brewster anomalies in both positive- and negative-refraction regimes of the dispersive metamaterial. These results suggest that Anderson localization of light could be explored to control and tune light propagation in disordered metamaterials.Comment: 4 two-column pages, 3 figure

    Fractal Conductance Fluctuations of Classical Origin

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    In mesoscopic systems conductance fluctuations are a sensitive probe of electron dynamics and chaotic phenomena. We show that the conductance of a purely classical chaotic system with either fully chaotic or mixed phase space generically exhibits fractal conductance fluctuations unrelated to quantum interference. This might explain the unexpected dependence of the fractal dimension of the conductance curves on the (quantum) phase breaking length observed in experiments on semiconductor quantum dots.Comment: 5 pages, 4 figures, to appear in PR

    Some Remarks about Variable Mass Systems

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    We comment about the general argument given to obtain the rocket equation as it is exposed in standard textbooks. In our opinion, it can induce students to a wrong answer when solving variable mass problems.Comment: 2 page
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