57 research outputs found

    Self-Tuning and de Sitter Brane Intersections in the 6-Dimensional Brane Models

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    We study the self-tuning of general brane junctions and brane networks on the 6-dimensional space-time. For the general brane junctions, there may exist one fine-tuning among the brane tensions. For the brane networks, similar to the 5-dimensional self-tuning brane models, the brane tensions can be set arbitrarily and there exists the singularity for the metric and bulk scalar. And if we want to regularize the singularity, we will introduce the fine-tuning among the brane tensions. In addition, because the 4-dimensional cosmological constant we observe may be positive and very small, we discuss the brane network with de Sitter brane intersections by introducing a bulk scalar.Comment: Latex, 11 page

    Two component dark matter with multi-Higgs portals

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    With the assistance of two extra groups, i.e., an extra hidden gauge group SU(2)DSU(2)_D and a global U(1)U(1) group, we propose a two component dark matter (DM) model. After the symmetry SU(2)D×U(1)SU(2)_D\times U(1) being broken, we obtain both the vector and scalar DM candidates. The two DM candidates communicate with the standard model (SM) via three Higgs as multi-Higgs portals. The three Higgs are mixing states of the SM Higgs, the Higgs of the hidden sector and real part of a supplement complex scalar singlet. We study relic density and direct detection of DM in three scenarios. The resonance behaviors and interplay between the two component DM candidates are represented through investigating of the relic density in the parameter spaces of the two DMs masses. The electroweak precision parameters constrains the two Higgs portals couplings (λm\lambda_m and δ2\delta_2). The relevant vacuum stability and naturalness problem in the parameter space of λm\lambda_m and δ2\delta_2 are studied as well. The model could alleviate these two problems in some parameter spaces under the constraints of electroweak precision observables and Higgs indirect search.Comment: 27 pages, 16 figures. Version accepted for publication in JHE

    Top Hypercharge

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    We propose a top hypercharge model with gauge symmetry SU(3)_C x SU(2)_L x U(1)_1 x U(1)_2 where the first two families of the Standard Model (SM) fermions are charged under U(1)_1 while the third family is charged under U(1)_2. The U(1)_1 x U(1)_2 gauge symmetry is broken down to the U(1)_Y gauge symmetry, when a SM singlet Higgs field acquires a vacuum expectation value. We consider the electroweak constraints, and compare the fit to experimental observables to that of the SM. We study the quark CKM mixing between the first two families and the third family, the neutrino masses and mixing, the flavour changing neutral current effects in meson mixing and decays, the Z' discovery potential at the Large Hadron Collider, the dark matter with a gauged Z_2 symmetry, and the Higgs boson masses.Comment: 17 pages and 4 figure

    Probing the CP-even Higgs Sector via H3H2H1H_3\to H_2H_1 in the Natural NMSSM

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    After the discovery of a Standard Model (SM) like Higgs boson, naturalness strongly favors the next to the Minimal Supersymmetric SM (NMSSM). In this letter, we point out that the most natural NMSSM predicts the following CP-even Higgs HiH_i sector: (A) H2H_2 is the SM-like Higgs boson with mass pushed-upward by a lighter H1H_1 with mass overwhelmingly within [mH2/2,mH2][m_{H_2}/2,m_{H_2}]; (B) mH32μ/sin2β300m_{H_3}\simeq 2\mu/\sin2\beta\gtrsim300 GeV; (C) H3H_3 has a significant coupling to top quarks and can decay to H1H2H_1H_2 with a large branching ratio. Using jet substructure we show that all the three Higgs bosons can be discovered via ggH3H1H2bbˉνjjgg\to H_3 \to H_1H_2\to b\bar b \ell\nu jj at the 14 TeV LHC. Especially, the LEP-LHC scenario with H198H_1\simeq98 GeV has a very good discovery potential.Comment: 5 pages, 2 figures. Some typos corrected and reference adde

    Brane Networks in AdS Space

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    We present static solutions to Einstein's equations corresponding to the most general network of NN orthogonal families of (2+N)(2+N)-branes in (4+N)(4+N)-dimensional AdSAdS spacetimes. The bulk cosmological constant can take a different value in each cell enclosed by intersecting branes and the extra dimensions can be compact or noncompact. In each family of branes the inter-brane spacing is arbitrary. The extra dimensions may be any or all of the manifolds, R1R^1, R1/Z2R^1/Z_2, S1S^1 and S1/Z2S^1/Z_2. Only when the extra dimensions are R1R^1 or/and R1/Z2R^1/Z_2, can networks consisting solely of positive tension branes be constructed. Such configurations may find application in models with localized gravity and symmetry breaking by shining.Comment: Version to appear in PL

    A Energy Balancing Control Strategy for Microgrid with Storage Systems

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    Abstract-In a microgrid, there is usually an energy storage system, while there is no continuous energy supply. The storage system does not only be used as a power supply in islanded state, but also could be taken as the demand side management devices in grid-connected state. In this paper, a system energy managing strategy is proposed. It can balance the energy in autonomous state, and manage power in gridconnected state under time-of-use pricing. Next, the droop control and economic dispatch method are introduced into the power management strategies to improve the power supply reliability and perform peak load shaving for maximum benefits. Finally, a simulation is shown to analyze the benefit from the strategies. And the applications of the economic dispatch method are discussed in the results under different operating conditions and market policies

    Flipped SU (5)× UX (1) models from F-theory

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    We systematically construct flipped SU(5) X U(1)_X models without and with bulk vector-like particles from F-theory. To realize the decoupling scenario, we introduce sets of vector-like particles in complete SU(5) X U(1) multiplets at the TeV scale, or at the intermediate scale, or at the TeV scale and high scale. To avoid the Landau pole problem for the gauge couplings, we can only introduce five sets of vector-like particles around the TeV scale. These vector-like particles can couple to the Standard Model singlet fields, and obtain suitable masses by Higgs mechanism. We study gauge coupling unification in detail. We show that the U(1)_X flux contributions to the gauge couplings preserve the SU(5) X U(1)_X gauge coupling unification. We calculate the SU(3)_C X SU(2)_L unification scales, and the SU(5) X U(1)_X unification scales and unified couplings. In most of our models, the high-scale or bulk vector-like particles can be considered as string-scale threshold corrections since their masses are close to the string scale. Futhermore, we discuss the phenomenological consequences of our models. In particular, in the models with TeV-scale vector-like particles, the vector-like particles can be observed at the Large Hadron collider, the proton decay is within the reach of the future Hyper-Kamiokande experiment, the lightest CP-even Higgs boson mass can be increased, the hybrid inflation can be naturally realized, and the correct cosmic primodial density fluctuations can be generated.Comment: RevTex4, 34 pages, 8 figures, 15 tables, version to appear in NP

    An aggregator-based dynamic pricing mechanism and optimal scheduling scheme for the electric vehicle charging

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    High penetration of electric vehicles (EVs) in an uncontrolled manner could have disruptive impacts on the power grid, however, such impacts could be mitigated through an EV demand response program. The successful implementation of an efficient, effective, and aggregated demand response from EV charging depends on the incentive pricing mechanism and the load shifting protocols. In this study, a genetic algorithm-based multi-objective optimization model is developed to generate hourly dynamic Time-of-Use electricity tariffs and facilitate the decision making in load scheduling. As an illustrative example, a case study was carried out to examine the effect of applying demand response for EVs in Beijing, China. With the assumptions made, the maximum peak load can be reduced by 9.8% and the maximum customer savings for the EVs owners can reach 11.85%, compared to the business-as-usual case
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