4,988 research outputs found

    W±H∓W^{\pm}H^{\mp} associated production at LHC in the general 2HDM with Spontaneous CP Violation

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    Spontaneous CP violation motivates the introduction of two Higgs doublets in the electroweak theory. Such a simple extension of the standard model has three neutral Higgs bosons and a pair charged Higgs, especially it leads to rich CP-violating sources including the induced Kobayashi-Maskawa CP-violating phase, the mixing of the neutral Higgs bosons due to the CP-odd Higgs and the effective complex Yukawa couplings of the charged and neutral Higgs bosons. Within this model, we present the production of a charged Higgs boson in association with a W boson at the LHC, and calculate in detail the cross section and the transverse momentum distribution of the associated W boson.Comment: 16 pages, 6 figures, omitted 3 figures, motivations for Type III 2HDM with SCPV is emphasized, to be published in PR

    Exclusive B→VVB \to VV Decays and CP Violation in the General two-Higgs-doublet Model

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    Using the general factorization approach, we present a detailed investigation for the branching ratios, CP asymmetries and longitudinal polarization fractions in all charmless hadronic B→VVB \to VV decays (except for the pure annihilation processes) within the most general two-Higgs-doublet model with spontaneous CP violation. It is seen that such a new physics model only has very small contributions to the branching ratios and longitudinal polarization fractions. However, as the model has rich CP-violating sources, it can lead to significant effects on the CP asymmetries, especially on those of penguin-dominated decay modes, which provides good signals for probing new physics beyond the SM in the future B-physics experiments.Comment: 17 pages, no figure

    Six-Quark Amplitudes from Fermionic MHV Vertices

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    The fermionic extension of the CSW approach to perturbative gauge theory coupled with fermions is used to compute the six-quark QCD amplitudes. We find complete agreement with the results obtained by using the usual Feynman rules.Comment: Latex file, 16 pages, 4 figure

    Thermodynamic properties of Ba1-xMxFe2As2 (M = La and K)

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    The specific heat C(T)C(T) of BaFe2_2As2_2 single crystal, electron-doped Ba0.7_{0.7}La0.3_{0.3}Fe2_2As2_2 and hole-doped Ba0.5_{0.5}K0.5_{0.5}Fe2_2As2_2 polycrystals were measured. For undoped BaFe2_2As2_2 single crystal, a very sharp specific heat peak was observed at 136 K. This is attributed to the structural and antiferromagnetic transitions occurring at the same temperature. C(T)C(T) of the electron-doped non-superconducting Ba0.7_{0.7}La0.3_{0.3}Fe2_2As2_2 also shows a small peak at 120 K, indicating a similar but weaker structural/antiferromagnetic transition. For the hole-doped superconducting Ba0.5_{0.5}K0.5_{0.5}Fe2_2As2_2, a clear peak of C/TC/T was observed at TcT_c = 36 K, which is the highest peak seen at superconducting transition for iron-based high-TcT_c superconductors so far. The electronic specific heat coefficient γ\gamma and Debye temperature ΘD\Theta_D of these compounds were obtained from the low temperature data

    Effects of water stress and nitrogen supply on leaf gas exchange and fluorescence parameters of Sophora davidii seedlings

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    Abstract Two-month-old seedlings of Sophora davidii were subjected to a randomized complete block design with three water (80, 40, and 20 % of water field capacity, i.e. FC 80 , FC 40 , and FC 20 ) and three N supply [N0: 0, Nl: 92 and Nh: 184 mg(N) kg -1 (soil)] regimes. Water stress produced decreased leaf area (LA) and photosynthetic pigment contents, inhibited photosynthetic efficiency, and induced photodamage in photosystem 2 (PS2), but increased specific leaf area (SLA). The decreased net photosynthetic rate (P N ) under medium water stress (FC 40 ) compared to control (FC 80 ) might result from stomatal limitations, but the decreased P N under severe water deficit (FC 20 ) might be attributed to non-stomatal limitations. On the other hand, N supply could improve photosynthetic capacity by increasing LA and photosynthetic pigment contents, and enhancing photosynthetic efficiency under water deficit. Moreover, N supply did a little in alleviating photodamages to PS2 caused by water stress. Hence water stress was the primary limitation in photosynthetic processes of S. davidii seedlings, while the photosynthetic characters of seedlings exhibited positive responses to N supply. Appropriate N supply is recommended to improve photosynthetic efficiency and alleviate photodamage under water stress

    High-precision numerical simulation for effect of casting speed on solidification of 40Cr during continuous billet casting

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    In order to study the effects of casting speed on the solidification process and optimize the process to reducedefects, a high-precision simulation model of solidification and heat transfer of square billet based on nailing test andtemperature measurement is presented. The experiments have proven that values calculated by the model fit well themeasured values and the relative error is maintained less than 2%. Some new rules about the relationships amongcasting speed, solidification end point and shell thickness are proposed in the paper for the first time
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