363 research outputs found

    On CP-Odd Effects in K_L \to 2\pi and K^{\pm} \to \pi^{\pm} \pi^{\pm} \pi^{\mp} Decays Generated by Direct CP Violation

    Full text link
    The amplitudes of the K^{\pm} \to 3\pi and K \to 2\pi decays are expressed in terms of different combinations of one and the same set of CP-conserving and CP-odd parameters. Extracting the magnitudes of these parameters from the data on K \to 2\pi decays, we estimate an expected CP-odd difference between the values of the slope parameters g^+ and g^- of the energy distributions of "odd" pions in K^+ \to \pi^+\pi^+\pi^- and K^- \to \pi^-\pi^-\pi^+ decays.Comment: 12 pages, no figure

    Emergency control algorithm for maintaining power stability based on newton's method

    Full text link
    The problem of stability boundary evaluation for the current power system state is of paramount importance for power system operation. In addition, maintaining stability after large scale disturbances has come to the fore in recent years. This paper presents the algorithm, which allows us to both evaluate the stability boundary of a power system and to calculate emergency control actions for maintaining stability in the case of blackout. The algorithm is based on Newton's method for solving optimization problems. There are a number of emergency actions algorithms in literature, but most of them use heuristic rules. On the contrary, the proposed method has a reasonable analytical background. Thus, having an adequate power system model, the proposed method is able to calculate more accurate control actions. The paper demonstrates the very basic idea of the approach with the simplest example. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

    Flavor Structure of Warped Extra Dimension Models

    Full text link
    We recently showed, in hep-ph/0406101, that warped extra dimensional models with bulk custodial symmetry and few TeV KK masses lead to striking signals at BB-factories. In this paper, using a spurion analysis, we systematically study the flavor structure of models that belong to the above class. In particular we find that the profiles of the zero modes, which are similar in all these models, essentially control the underlying flavor structure. This implies that our results are robust and model independent in this class of models. We discuss in detail the origin of the signals in B-physics. We also briefly study other NP signatures that arise in rare K decays (KπννK \to \pi \nu \nu), in rare top decays [tcγ(Z,gluon)t \to c \gamma (Z, gluon)] and the possibilty of CP asymmetries in D0D^0 decays to CP eigenstates such as KSπ0K_S \pi^0 and others. Finally we demonstrate that with light KK masses, 3\sim3 TeV, the above class of models with anarchic 5D5D Yukawas has a ``CP problem'' since contributions to the neutron electric dipole moment are roughly 20 times larger than the current experimental bound. Using AdS/CFT correspondence, these extra-dimensional models are dual to a purely 4D strongly coupled conformal Higgs sector thus enhancing their appeal.Comment: 41 pages, 52 pages including appendice

    Neutron-Electron EDM Correlations in Supersymmetry and Prospects for EDM Searches

    Full text link
    Motivated by recent progress in experimental techniques of electric dipole moment (EDM) measurements, we study correlations between the neutron and electron EDMs in common supersymmetric models. These include minimal supergravity (mSUGRA) with small CP phases, mSUGRA with a heavy SUSY spectrum, the decoupling scenario and split SUSY. In most cases, the electron and neutron EDMs are found to be observable in the next round of EDM experiments. They exhibit certain correlation patterns. For example, if d_n ~ 10^{-27} e cm is found, d_e is predicted to lie in the range 10^{-28}-10^{-29} e cm.Comment: 16 pages,12 figures. To appear in JHEP. A note on stability of the correlations added in Conclusions; refs. and footnotes adde

    On the Role of FSI in K -> 2\pi Decay

    Full text link
    Contrary to wide-spread opinion that the final state interaction (FSI) enlarges the amplitude , we argue that FSI is not able to increase the absolute value of this amplitude.Comment: 10 pages, minor correction

    Scalar meson dynamics in Chiral Perturbation Theory

    Full text link
    A comparison of the linear sigma model (Lσ\sigmaM) and Chiral Perturbation Theory (ChPT) predictions for pion and kaon dynamics is presented. Lowest and next-to-leading order terms in the ChPT amplitudes are reproduced if one restricts to scalar resonance exchange. Some low energy constants of the order p4p^4 ChPT Lagrangian are fixed in terms of scalar meson masses. Present values of these low energy constants are compatible with the Lσ\sigmaM dynamics. We conclude that more accurate values would be most useful either to falsify the Lσ\sigmaM or to show its capability to shed some light on the controversial scalar physics.Comment: 9 pages, REVTeX 4.0. Final version accepted for publicatio

    Characterization of Spatial Coherence of Synchrotron Radiation with Non-Redundant Arrays of Apertures

    Full text link
    We present a method to characterize the spatial coherence of soft X-ray radiation from a single diffraction pattern. The technique is based on scattering from non-redundant arrays (NRA) of slits and records the degree of spatial coherence at several relative separations from one to 15 microns, simultaneously. Using NRAs we measured the transverse coherence of the X-ray beam at the XUV X-ray beamline P04 of the PETRA III synchrotron storage ring as a function of different beam parameters. To verify the results obtained with the NRAs additional Young's double pinhole experiments were conducted and show good agreement.Comment: 15 pages, 6 figures, 2 tables, 42 reference

    The isospin symmetry breaking effects in Ke4K_{e4} decays

    Full text link
    The Fermi-Watson theorem is generalized to the case of two coupled channels with different masses and applied to final state interaction in Ke4K_{e4} decays. The impact of considered effect on the phase of the ππ\pi\pi scattering is estimated and shown that it can be crucial for scattering lengths extraction from experimental data on Ke4K_{e4} decays

    Revealing three-dimensional structure of individual colloidal crystal grain by coherent x-ray diffractive imaging

    Get PDF
    We present results of a coherent x-ray diffractive imaging experiment performed on a single colloidal crystal grain. The full three-dimensional (3D) reciprocal space map measured by an azimuthal rotational scan contained several orders of Bragg reflections together with the coherent interference signal between them. Applying the iterative phase retrieval approach, the 3D structure of the crystal grain was reconstructed and positions of individual colloidal particles were resolved. As a result, an exact stacking sequence of hexagonal close-packed layers including planar and linear defects were identified.Comment: 8 pages, 5 figure
    corecore