6,217 research outputs found

    Derivation of Electroweak Chiral Lagrangian from One Family Technicolor Model

    Full text link
    Based on previous studies deriving the chiral Lagrangian for pseudo scalar mesons from the first principle of QCD in the path integral formalism, we derive the electroweak chiral Lagrangian and dynamically compute all its coefficients from the one family technicolor model. The numerical results of the p4p^4 order coefficients obtained in this paper are proportional to the technicolor number NTCN_{\rm TC} and the technifermion number NTFN_{\rm TF}, which agrees with the arguments in previous works, and which confirms the reliability of this dynamical computation.Comment: 6 page

    Self learning research on rolling force model of hot strip rolling based on improved adaptive difference

    Get PDF
    In order to improve the prediction accuracy of the rolling force Self-learning Model and change the phenomenon that the learning coefficient is unstable and the optimization process is not reasonable due to the experience value of the self-learning factor in the traditional self-learning, this paper proposes an improved adaptive differential evolution (IADE) algorithm based on the standard differential evolution algorithm to solve and optimize the problem quickly. The prediction accuracy of rolling force model is improved. The experimental results show that the prediction accuracy of IADE algorithm is lower than that of the traditional model, which can effectively improve the prediction accuracy

    Self learning research on rolling force model of hot strip rolling based on improved adaptive difference

    Get PDF
    In order to improve the prediction accuracy of the rolling force Self-learning Model and change the phenomenon that the learning coefficient is unstable and the optimization process is not reasonable due to the experience value of the self-learning factor in the traditional self-learning, this paper proposes an improved adaptive differential evolution (IADE) algorithm based on the standard differential evolution algorithm to solve and optimize the problem quickly. The prediction accuracy of rolling force model is improved. The experimental results show that the prediction accuracy of IADE algorithm is lower than that of the traditional model, which can effectively improve the prediction accuracy

    Probing the topcolor-assisted technicolor model via the single t-quark production at Hadron colliders

    Full text link
    In this paper, we systematically study the contribution of the TC2 model to the single t-quark production at the Hadron colliders, specially at the LHC. The TC2 model can contribute to the cross section of the single t-quark production in two different ways. First, the existence of the top-pions and top-higgs can modify the WtbWtb coupling via their loop contributions, and such modification can cause the correction to the cross sections of all three production modes. Our study shows that this kind of correction is negative and very small in all cases. Thus it is difficult to observe such correction even at the LHC. On the other hand, there exist the tree-level FC couplings in the TC2 model which can also contribute to the cross sections of the tqtq and tbˉt\bar{b} production processes. The resonant effect can greatly enhance the cross sections of the tqtq and tbˉt\bar{b} productions. The first evidence of the single t-quark production has been reported by the D0D0 collaboration and the measured cross section for the single t-quark production of σ(ppˉtb+X,tqb+X)\sigma(p\bar{p}\to tb+X,tqb+X) is compatible at the 10% level with the standard model prediction. Because the light top-pion can make great contribution to the tbˉt\bar{b} production, the top-pion mass should be very large in order to make the predicted cross section in the TC2 model be consistent with the Tevatron experiments. More detailed information about the top-pion mass and the FC couplings in the TC2 model should be obtained with the running of the LHC.Comment: 30 pages, 3 tables, 10 figure

    Mgb2 Nonlinear Properties Investigated under Localized High RF Magnetic Field Excitation

    Full text link
    In order to increase the accelerating gradient of Superconducting Radio Frequency (SRF) cavities, Magnesium Diboride (MgB2) opens up hope because of its high transition temperature and potential for low surface resistance in the high RF field regime. However, due to the presence of the small superconducting gap in the {\pi} band, the nonlinear response of MgB2 is potentially quite large compared to a single gap s-wave superconductor (SC) such as Nb. Understanding the mechanisms of nonlinearity coming from the two-band structure of MgB2, as well as extrinsic sources, is an urgent requirement. A localized and strong RF magnetic field, created by a magnetic write head, is integrated into our nonlinear-Meissner-effect scanning microwave microscope [1]. MgB2 films with thickness 50 nm, fabricated by a hybrid physical-chemical vapor deposition technique on dielectric substrates, are measured at a fixed location and show a strongly temperature-dependent third harmonic response. We propose that at least two mechanisms are responsible for this nonlinear response, one of which involves vortex nucleation and penetration into the film. [1] T. M. Tai, X. X. Xi, C. G. Zhuang, D. I. Mircea, S. M. Anlage, "Nonlinear Near-Field Microwave Microscope for RF Defect Localization in Superconductors", IEEE Trans. Appl. Supercond. 21, 2615 (2011).Comment: 6 pages, 6 figure

    Investigation of infrared phonon modes in multiferroic single-crystal FeTe2_{2}O5_{5}Br

    Get PDF
    Reflection and transmission as a function of temperature (5--300 K) have been measured on single crystals of the multiferroic compound FeTe2_{2}O5_{5}Br utilizing light spanning the far infrared to the visible portions of the electromagnetic spectrum. The complex dielectric function and optical properties were obtained via Kramers-Kronig analysis and by fits to a Drude-Lortentz model. Analysis of the anisotropic excitation spectra via Drude-Lorentz fitting and lattice dynamical calculations have lead to the observation of all 52 IR-active modes predicted in the acac plane and 43 or the 53 modes predicted along the b axis of the monoclinic cell. Assignments to groups (clusters) of phonons have been made and trends within them are discussed in light of our calculated displacement patterns.Comment: 9 pages, 7 figure
    corecore