2,203 research outputs found

    A More Flavored Higgs boson in Supersymmetric models

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    A More flavored Higgs boson arises when the flavor structure encoded in SUSY extensions of the SM is transmited to the Higgs sector. The flavor-Higgs transmition mechanism can have a radiative or mixing origin, as it is illustrated with several examples, and can produce interesting Higgs signatures that can be probed at future high-energy colliders. Within the MSSM, the flavor mediation mechanism can be of radiative type, as it is realized trhough gaugino-slepton loops, which transmit the flavor structture of the soft-breaking sector to the Higgs bosons. In particular we focus on evaluating the contributions from the general trilinear terms to the lepton flavor violating Higgs (LFV) vertices. On the other hand, as an example of flavor mediation through mixing, we discuss an E_6 inspired multi-Higgs model, with an abelian flavor symmetry, where LFV as well as lepton flavor conserving Higgs effects are found to arise, though in this case at tree-level. We find that Tevatron and LHC can provide information on the flavor structure of these models through the detection of the LFV higgs mode h-> tau+mu, while NLC can perform high-precision measurements of the LFC mode h-> tau tau.Comment: 17 pages, 5 tables, 3 figures; corrected mistake in last section, results changed but conclusions remmai

    A phytosociological survey of the boreal forest (Vaccinio-Piceetea) in North America

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    A survey of syntaxa of vegetation of North American boreal forests (class Vaccinio-Piceetea) is presented. This phytosociological survey, carried out combining the Braun-Blanquet method with numerical syntaxonomical analyses (cluster and correspondence analysis), describes the associations of the North American boreal forests, which have several species, varieties or vicariant species in common with their Eurasian counterparts, and can be placed in the class Vaccinio-Piceetea. By means of tabular and multivariate analyses, 2084 North American relevés were compared with 3273 relevés from European, Japanese and Korean boreal forest, to describe and typify 4 orders, 10 alliances and 37 associations. Diagnostic tables, ordination, clustering, and climatic, edaphic and biogeographical data were used to show floristic affinities among these syntaxa and interpret their distribution areas. Syntaxa were briefly characterized by their floristic composition, physiognomy, succession, zonation, and biogeographical distribution

    Testing models with non-minimal Higgs sector through the decay t->q+WZ

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    We study the contribution of charged Higgs boson to the rare decay of the top quark t->q+WZ (q=d,s,b) in models with Higgs sector that includes doublets and triplets. Higgs doublets are needed to couple charged Higgs with quarks, whereas the Higgs triplets are required to generate the non-standard vertex HWZ at tree-level. It is found that within a model that respect the custodial SU(2) symmetry and avoids flavour changing neutral currents by imposing discrete symmetries, the decay mode t->b+WZ, can reach a branching ratio of order 0.0178, whereas the decay modes t->(d,s)+WZ, can reach a similar branching ratio in models where flavour changing neutral currents are suppressed by flavour symmetries.Comment: Typeset using REVTEX and EPSF, 5 pag, 2 figure

    Mass matrix Ansatz and lepton flavor violation in the THDM-III

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    Predictive Higgs-fermion couplings can be obtained when a specific texture for the fermion mass matrices is included in the general two-Higgs doublet model. We derive the form of these couplings in the charged lepton sector using a Hermitian mass matrix Ansatz with four-texture zeros. The presence of unconstrained phases in the vertices phi-li-lj modifies the pattern of flavor-violating Higgs interactions. Bounds on the model parameters are obtained from present limits on rare lepton flavor violating processes, which could be extended further by the search for the decay tau -> mu mu mu and mu-e conversion at future experiments. The signal from Higgs boson decays phi -> tau mu could be searched at the large hadron collider (LHC), while e-mu transitions could produce a detectable signal at a future e mu-collider, through the reaction e mu -> h0 -> tau tau.Comment: 17 pages, 9 figure

    Probing the mechanism of EWSB with a rho parameter defined in terms of Higgs couplings

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    A definition of the rho parameter based on the Higgs couplings with the gauge bosons, rho_h= g_{hWW}}/c^2_W g_{hZZ}, is proposed as a new probe into the origin of the mechanism of electroweak symmetry breaking. While ρh=1\rho_h=1 holds in the SM, deviations from one are predicted in models with extended Higgs sector. We derive a general expresion of rho_h for a model with arbitrary Higgs multiplets, and discuss its size within the context of specific models with Higgs triplets, including the ``Little Higgs'' models recently proposed. We find the even for Higgs models that incorporate the custodial symmetry to make rho=1, one could have rho_h\neq 1, which could be tested at the level of a few percent, with the precision Higgs meassurements expected at the NLC.Comment: 12 pages, 2 figure

    New Higgs signals induced by mirror fermion mixing effects

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    We study the conditions under which flavor violation arises in scalar-fermion interactions, as a result of the mixing phenomena between the standard model and exotic fermions. Phenomenological consequences are discussed within the specific context of a left-right model where these additional fermions have mirror properties under the new SU(2)_R gauge group. Bounds on the parameters of the model are obtained from LFV processes; these results are then used to study the LFV Higgs decays (H --> tau l_j, l_j = e, mu), which reach branching ratios that could be detected at future colliders.Comment: 12 pages, 2 figures, ReVTex4, graphicx, to be published in Phys. Rev.

    H^+ -> W^+ l_i^- l_j^+$ decay in the two Higgs doublet model

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    We study the lepton flavor violating H^+ -> W^+ l_i^- l_j^+ and the lepton flavor conserving $H^+ -> W^+ l_i^- l_i^+ (l_i=\tau, l_j=\mu) decays in the general 2HDM, so called model III. We estimate the decay width \Gamma for LFV (LFC) at the order of the magnitude of (10^{-11}-10^{-5}) GeV ((10^{-9}-10^{-4}) GeV), for 200 GeV\leq m_{H^\pm}\leq 400 GeV, and the intermediate values of the coupling \bar{\xi}^{E}_{N,\tau \mu}\sim 5 GeV (\bar{\xi}^{E}_{N,\tau \tau}\sim 30 GeV). We observe that the experimental result of the process under consideration can give comprehensive information about the physics beyond the standard model and the existing free parameters.Comment: 8 pages, 7 Figure

    An effective lagrangian description of charged Higgs decays H^+ -> Wg, WZ and Wh

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    Charged Higgs decays are discussed within an effective lagrangian extension of the two-higgs doublet model, assuming new physics appearing in the Higgs sector of this model. Low energy constrains are used to imposse bounds on certain dimension -six operators that describe the modified charged Higgs interactions. These bounds are used then to study the decays H^+ -> Wg, WZ and Wh, which can have branching ratios of order 10^-5, 10^-1 and O(1), respectively; thse modes are thus sensitive probes of the symmetries of the Higgs sector that could be tested at future colliders.Comment: 15 pages, 3 figure

    On the optimal demand-side management in microgrids through polygonal composition

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    This article presents a novel methodology for energy management in microgrids focused on the demand side. It is inspired by the Tangram puzzle. The energy demand and production profiles are represented by polygons and managed through computational geometry. Therefore, an optimization problem is defined to place n energy demand profiles (pieces) to cover the total energy production profile (target shape). The optimization problem is addressed with a genetic algorithm. It tries to calculate the optimal positions of the polygons of the demands covering the maximum energy production. Since the referred production comes from renewable energy sources in the microgrid, this method allows reducing both the consumption of fossil fuels and energy bills

    Coupling between counterpropagating cladding modes in fiber Bragg gratings

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    We present an experimental demonstration of energy transfer between counterpropagating cladding modes in a fiber Bragg grating (FBG). A strong FBG written in a standard photosensitive optical fiber is illuminated with a single cladding mode, and the power transferred between the forward propagating cladding mode and different backward propagating cladding modes is measured by using two auxiliary long period gratings. Resonances between cladding modes having 30 pm bandwidth and 8 dB rejection have been observed
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