4,359 research outputs found

    Top-bottom mass hierarchy, sμs-\mu puzzle and gauge coupling unification with split multiplets

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    A supersymmetric 5D SU(5) grand unification is considered. The SU(5) is broken down to GSM=SU(3)×SU(2)×U(1)G_{SM}=SU(3)\times SU(2)\times U(1) by the Z2×Z2Z_2\times Z_2' assignment of the bulk field(s). The matter fields are located at the fixed point(s). In the bulk, a Higgs multiplet 5ˉH\bar 5_H(containing the bottom doublet H1H_1) and the SU(5) gauge multiplet are located. At one fixed point, H2H_2(the top doublet) and the standard model matter multiplets are presented. Because of the difference of the locations of H1H_1 and H2H_2, one can obtain a hierarchy between top and bottom Yukawa couplings. We also present a possibility to understand the sμs-\mu mass puzzle in this framework of the split multiplet.Comment: LaTeX file of 17 pages including 3 eps figures. A note is added and typo errors corrected. To appear in Euro. Phys. J.

    Re-derivation of Young’s Equation, Wenzel Equation, and Cassie-Baxter Equation Based on Energy Minimization

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    Recently, Young’s equation, the Wenzel equation, and the Cassie-Baxter equation have been widely used with active research on superhydrophobic surfaces. However, experiments showed that the Wenzel equation and the Cassie-Baxter equation were not derived correctly. They should be reviewed on a firm physical ground. In this study, these equations are re-derived from a thermodynamic point of view by employing energy minimization and variational approach. The derivations provide a deeper understanding of these equations and the behavior of a contact angle. Also, in applying these equations, the limitations and considerations are discussed. It is expected that this study will provide a theoretical basis for the careful use of these equations on rough or chemically heterogeneous surfaces

    Practical Design of Green Catalysts for PET Recycling and Energy Conversion

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    The recycling of chemicals and generation of alternative energy are central topics in the efforts toward sustainable development. Among these, research on plastics recycling and fuel cells has received significant attention, with the aim of designing novel catalysts to improve yield and efficiency. We highlight our work on these areas focusing on the chemical depolymerization of polyethylene terephthalate (PET) to recover its constituent monomer and the development of high-performance anode catalysts for polymer electrolyte membrane fuel cells (PEMFC). We demonstrate various flexible yet practical synthesis strategies (e.g. ultrasound-assisted deposition and biopolymer coating) that were used to obtain catalytic properties optimized for these applications. The effectiveness and simplicity of these methods render the catalysts to be truly green — from synthesis up to process application

    125 GeV Higgs as a pseudo-Goldstone boson in supersymmetry with vector-like matters

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    We propose a possibility of the 125 GeV Higgs being a pseudo-Goldstone boson in supersymmetry with extra vector-like fermions. Higgs mass is obtained from loops of top quark and vector-like fermions from the global symmetry breaking scale f at around TeV. The mu, Bmu/mu \sim f are generated from the dynamics of global symmetry breaking and the Higgs quartic coupling vanishes at f as tan beta \simeq 1. The relation of msoft \sim 4πMZ4\pi M_Z with f \sim mu \sim m_soft \sim TeV is obtained and large mu does not cause a fine tuning for the electroweak symmetry breaking. The Higgs to di-photon rate can be enhanced from the loop of uncolored vector-like matters. The stability problem of Higgs potential with vector-like fermions can be nicely cured by the UV completion with the Goldstone picture.Comment: 28 pages, 8 figure

    Structural and Thermal Stabilities of LixCoO2 cathode for LIB studied by a temperature programmed reduction (TPR).

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    In recent years, research and development of battery technology has primarily been focused on the lithium-ion batteries (LIB) due to the high specific energy density, and therefore are widely utilized as the energy source for portable electronics and electric vehicles. However, the battery safety is an essential issue to overcome, as the battery are required higher power density and larger capacity. Many efforts have been conducted to improve the safety of LIB in the active material processing, as well as the cell battery manufacturing and management technology
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