4,872 research outputs found

    Two-Loop O(αt2){\cal O}(\alpha_t^2) Corrections to the Neutral Higgs Boson Masses in the CP-Violating NMSSM

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    We present our calculation of the two-loop corrections of O(αt2){\cal O}(\alpha_t^2) to the neutral Higgs boson masses of the CP-violating Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM). The calculation is performed in the Feynman diagrammatic approach in the gaugeless limit at vanishing external momentum. We apply a mixed DR‾\overline{\mathrm{DR}}-on-shell (OS) renormalization scheme for the NMSSM input parameters. Furthermore, we exploit a DR‾\overline{\mathrm{DR}} as well as an OS renormalization in the top/stop sector. The corrections are implemented in the Fortran code NMSSMCALC for the calculation of the Higgs spectrum both in the CP-conserving and CP-violating NMSSM. The code also provides the Higgs boson decays including the state-of-the-art higher-order corrections. The corrections computed in this work improve the already available corrections in NMSSMCALC which are the full one-loop corrections without any approximation and the two-loop O(αtαs){\cal O}(\alpha_t \alpha_s) corrections in the gaugeless limit and at vanishing external momentum. Depending on the chosen parameter point, we find that the O(αtαs+αt2){\cal O}(\alpha_t \alpha_s + \alpha_t^2) corrections add about 4-7% to the one-loop mass of the SM-like Higgs boson for DR‾\overline{\mathrm{DR}} renormalization in the top/stop sector and they reduce the mass by about 6-9% if OS renormalization is applied. For an estimate of the theoretical uncertainty we vary the renormalization scale and change the renormalization scheme and show that care has to be taken in the corresponding interpretation

    GEODYN programmer's guide, volume 2, part 2

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    A computer program for executive control routine for orbit integration of artificial satellites is presented. At the beginning of each arc, the program initiates required constants as well as the variational partials at epoch. If epoch needs to be reset to a previous time, the program negates the stepsize, and calls for integration backward to the desired time. After backward integration is completed, the program resets the stepsize to the proper positive quantity

    Suppression of interdiffusion in GaAs/AlGaAs quantum-well structure capped with dielectric films by deposition of gallium oxide

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    In this work, different dielectric caps were deposited on the GaAs/AlGaAs quantum well(QW) structures followed by rapid thermal annealing to generate different degrees of interdiffusion. Deposition of a layer of GaxOy on top of these dielectric caps resulted in significant suppression of interdiffusion. In these samples, it was found that although the deposition of GaxOy and subsequent annealing caused additional injection of Ga into the SiOâ‚‚ layer, Ga atoms were still able to outdiffuse from the GaAsQW structure during annealing, to generate excess Ga vacancies. The suppression of interdiffusion with the presence of Ga vacancies was explained by the thermal stress effect which suppressed Ga vacancydiffusion during annealing. It suggests that GaxOy may therefore be used as a mask material in conjunction with other dielectric capping layers in order to control and selectively achieve impurity-free vacancy disordering.J. Wong-Leung, P. N. K. Deenapanray, and H. H. Tan acknowledge the fellowships awarded by the Australian Research Council
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