232 research outputs found

    CP violation in K±π0π0π±K^{\pm}\to\pi^0\pi^0\pi^{\pm} decay

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    CP violation leads to a difference between the parameters g+g^+ and gg^- describing the energy distributions of the charged pions produced in the K+π0π0π+K^+ \to\pi^0 \pi^0 \pi^+ and Kπ0π0πK^- \to \pi^0\pi^0 \pi^- decays. We study the difference (g+g)(g^+ - g^-) as a function of the relative contributions from the QCD-penguin and the electroweak-penguin diagrams. We find that the combination of these contributions in (g+g)(g^+ - g^-) is very similar to the corresponding one defining the parameter ϵ\epsilon' in the KL2πK_L \to 2\pi decays. This observation allows a determination of the value of (g+g)(g^+ - g^-), using data on ϵ\epsilon'

    An experimental study of concrete resistivity and the effects of electrode configuration and current frequency on measurement

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    Electrical resistivity, a measurable parameter of the state of concrete, plays an important role in the assessment of reinforced concrete structures. An experimental study using two-electrode method has been conducted to evaluate the resistivity of Portland cement concrete. Internal and external electrodes were varied in order to understand effect of the electrodes configuration, where carbon fibre (CF) sheets were employed as the internal electrodes and CF and copper sheets were used as external electrodes. Furthermore, frequency of applied current was varied from low to high, to identify the most suitable frequency that can be utilized for stable and reliable results. Optimised internal electrodes configuration and the current frequency of 10,000 Hz were used to measure the resistivity on a series of concrete cubes, which were made using three different water to cement ratios and four different chloride contents

    Modelling the electrical resistivity of concrete with varied water and chloride contents

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    The electrical resistivity of concrete is an important property in the assessment of reinforcement corrosion in concrete and an essential parameter in the design and operation of cathodic protection for reinforced-concrete (RC) structures. Water and chloride contents in concrete are highly variable in RC structures in real-world hostile environments, meaning that characterisation of their coupled effects on concrete electrical resistivity is important. The currently available models are investigated in this paper. As all the current models are purely empirical, an improvement with a semi-empirical model is proposed. The improvement highlights the intrinsic linkage between concrete electrical resistivity and water content and the pore size distribution of concrete. The proposed model was tested using two sets of experimental data and was also compared with other two empirical models

    Hydrothermal synthesis of zeolites from coal fly ash

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    The fly ash, from the combustion of coal to produce energy and heat, is an industrial waste, in which large accumulations represent a serious environmental threat. To reduce the environmental burden and improve the economic benefits of energy production, the science and industry focus on the transformation of coal combustion byproducts into new functional materials. The fly ash was studied by modern analytical methods. As a result of the hydrothermal reaction, several types of zeolites were synthesised from the fly ash: analcime, faujasite (zeolite X) and gismondine (zeolite P). It was shown that the experimental conditions (temperature, reaction time and alkali concentration) have a significant influence on the type of zeolite and its content in the reaction products. The series of experiments resulted in building approximate crystallisation field of zeolites and other phases as the first stage of the formation of ceramic membrane and other materials

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

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    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

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

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    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

    Constraining CP Violating Phases of the MSSM

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    Possible CP violation in supersymmetric (SUSY) extensions of the Standard Model (SM) is discussed. The consequences of CP violating phases in the gaugino masses, trilinear soft supersymmetry-breaking terms and the `mu' parameter are explored. Utilizing the constraints on these parameters from electron and neutron electric dipole moments, possible CP violating effects in B-physics are shown. A set of measurements from the B-system which would overconstrain the above CP violating phases is illustrated.Comment: 14 pages, 6 figure
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