3,524 research outputs found

    Wrong sign and symmetric limits and non-decoupling in 2HDMs

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    We analyse the possibility that, in two Higgs doublet models, one or more of the Higgs couplings to fermions or to gauge bosons change sign, relative to the respective Higgs Standard Model couplings. Possible sign changes in the coupling of a neutral scalar to charged ones are also discussed. These \textit{wrong signs} can have important physical consequences, manifesting themselves in Higgs production via gluon fusion or Higgs decay into two gluons or into two photons. We consider all possible wrong sign scenarios, and also the \textit{symmetric limit}, in all possible Yukawa implementations of the two Higgs doublet model, in two different possibilities: the observed Higgs boson is the lightest CP-even scalar, or the heaviest one. We also analyse thoroughly the impact of the currently available LHC data on such scenarios. With all 8 TeV data analysed, all wrong sign scenarios are allowed in all Yukawa types, even at the 1σ\sigma level. However, we will show that B-physics constraints are crucial in excluding the possibility of wrong sign scenarios in the case where tanβ\tan \beta is below 1. We will also discuss the future prospects for probing the wrong sign scenarios at the next LHC run. Finally we will present a scenario where the alignment limit could be excluded due to non-decoupling in the case where the heavy CP-even Higgs is the one discovered at the LHC.Comment: 20 pages, 15 figure

    The CP-conserving 2HDM after the 8 TeV run

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    We confront the most common CP-conserving 2HDM with the LHC data analysed so far while taking into account all previously available experimental data. A special allowed corner of the parameter space is analysed - the so-called wrong-sign scenario where the Higgs coupling to down-type quarks changes sign relative to the Standard Model while the coupling to the massive vector bosons does not.Comment: 6 pages, 2 figures, to appear in the proceedings of the 22nd International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS 2014), 28 April - 2 May 2014 Warsaw (Poland

    Active Metal Brazing of Machinable Aluminum Nitride-Based Ceramic to Stainless Steel

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    Shapal!-M machinable AlN-based ceramic and AISI 304 stainless steel were joined by active metal brazing, at 750, 800, and 850 !C, with a dwell stage of 10 min at the processing temperature, using a 59Ag- 27.25Cu-12.5In-1.25Ti (wt.%) filler foil. The influences of temperature on the microstructural features of brazed interfaces and on the shear strength of joints were assessed. The interfacial microstructures were analyzed by scanning electron microscopy (SEM), and the composition of the phases detected at the interfaces was evaluated by energy dispersive X-ray spectroscopy (EDS). The fracture surfaces of joints were analyzed by SEM, EDS, and GIXRD (Grazing Incidence X-Ray Diffraction). Reaction between the liquid braze and both base materials led to the formation of a Ti-rich layer, adjacent to each base material. Between the Ti-rich layers, the interfaces consist of a (Ag) solid-solution matrix, where coarse (Cu) particles and either Cu-In or Cu-In-Ti and Cu-Ti intermetallics phases are dispersed. The stronger joints, with shear strength of 220±32 MPa, were produced after brazing at 800 !C. Fracture of joints occurred preferentially not only through the ceramic sample but also across the adjoining TiN layer, independent of the brazing temperature

    The Wrong Sign limit in the 2HDM

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    A sign change in the Higgs couplings to fermions and massive gauge bosons is still allowed in the framework of two-Higgs doublet models (2HDM). In this work we discuss the possible sign changes in the Higgs couplings to fermions and gauge bosons, while reviewing the status of the 8-parameter CP-conserving 2HDM after the Large Hadron Collider 8 TeV run.Comment: 6 pages, 3 figures. Proceedings of the Second Annual Conference on Large Hadron Collider Physics, Columbia University, New York, U.S.A, June 2-7, 2014. arXiv admin note: text overlap with arXiv:1407.439

    A Educação ambiental como instrumento para a melhoria da gestão dos resíduos sólidos nas organizações públicas e privadas: contexto, legislação e ações estratégicas.

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    Este trabalho parte de um problema do presente, o alto consumo de bens materiais e seus desperdícios nas organizações públicas e privadas, e se propõe a oferecer diretrizes em educação ambiental para administrar e diminuir a produção de resíduos sólidos comuns, como papel, plástico, vidro e metal. Na Empresa Brasileira de Pesquisa Agropecuária (Embrapa), no Estado do Amapá, desenvolve-se um programa de gestão ambiental, cuja ênfase no gerenciamento desses resíduos está em fase de implementação, com a construção de uma área para processamento do lixo produzido diariamente. Dessa forma, o objetivo geral deste documento é apresentar uma pequena abordagem sobre a evolução da questão ambiental, sugerindo ações para a redução do consumo de materiais diversos nas instituições, tendo a educação ambiental como instrumento estratégico para internalizar os procedimentos de melhoria da qualidade do meio ambiente no trabalho, conduzindo os servidores a uma mudança de comportamento, na busca de soluções concretas para as alterações nos padrões insustentáveis da vida moderna.bitstream/item/62290/1/AP-2012-Educacao-ambiental-Documentos-73.pd

    Large and small-scale structures and the dust energy balance problem in spiral galaxies

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    The interstellar dust content in galaxies can be traced in extinction at optical wavelengths, or in emission in the far-infrared. Several studies have found that radiative transfer models that successfully explain the optical extinction in edge-on spiral galaxies generally underestimate the observed FIR/submm fluxes by a factor of about three. In order to investigate this so-called dust energy balance problem, we use two Milky Way-like galaxies produced by high-resolution hydrodynamical simulations. We create mock optical edge-on views of these simulated galaxies (using the radiative transfer code SKIRT), and we then fit the parameters of a basic spiral galaxy model to these images (using the fitting code FitSKIRT). The basic model includes smooth axisymmetric distributions along a S\'ersic bulge and exponential disc for the stars, and a second exponential disc for the dust. We find that the dust mass recovered by the fitted models is about three times smaller than the known dust mass of the hydrodynamical input models. This factor is in agreement with previous energy balance studies of real edge-on spiral galaxies. On the other hand, fitting the same basic model to less complex input models (e.g. a smooth exponential disc with a spiral perturbation or with random clumps), does recover the dust mass of the input model almost perfectly. Thus it seems that the complex asymmetries and the inhomogeneous structure of real and hydrodynamically simulated galaxies are a lot more efficient at hiding dust than the rather contrived geometries in typical quasi-analytical models. This effect may help explain the discrepancy between the dust emission predicted by radiative transfer models and the observed emission in energy balance studies for edge-on spiral galaxies.Comment: 9 pages, 5 figures, accepted for publication in A&
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