On a Three-Dimensional Gravity Model with Higher Derivatives

The purpose of this work is to present a model for 3D massive gravity with topological and higher-derivative terms. Causality and unitarity are discussed at tree-level. Power-counting renormalizability is also contemplated.Comment: 9 pages, Latex, no figures; to be published in Gen. Rel. Gra

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

We study the muon anomalous magnetic moment $(g-2)_{\mu}$ 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 ($H^{\pm \pm}$) and gauge boson ($U^{\pm \pm}$), new singly charged vectors ($V^{\pm}$) and a $Z^{\prime}$ boson, each of which might give a sizeable contribution to the $(g-2)_{\mu}$. We compute the 1-loop contributions from all these new particles to the $(g-2)_{\mu}$. 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 $SU(3)_L\otimes U(1)_N$ symmetry breaking $v_{\chi} \sim 2$ 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 $v_\chi > 2.7$ 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

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

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

Street space allocation – new tools and methods, with a Lisbon application [Full paper]

The allocation of space to different uses in busy city streets is a complex and conten-tious process. Decisions to reallocate streetspace are usually based on public consulta-tion and modelling of a few street redesign options, but results are not compared sys-tematically. In addition, the set of options considered is usually incomplete. This paper proposes a new process for streetspace reallocation, including option generation (with online and physical tools), estimation of performance indicators (with microsimula-tion), and comparison of options (with a new appraisal tool). The process was applied to the redesign of a busy street in Lisbon. Several options were generated, all involving reducing the space allocated to general motorised traffic. Microsimulation showed that allocating more space to some street uses also bring benefits to other uses. The option to allocate more space to both bus users and pedestrians does not deteriorate move-ment by other modes. However, appraisal showed that some redesign options go against technical/design standards or political priorities