4,169,853 research outputs found

    The Experimental Status of the Standard Electroweak Model at the End of the LEP-SLC Era

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    A method is proposed to calculate the confidence level for agreement of data with the Standard Model (SM) by combining information from direct and indirect Higgs Boson searches. Good agreement with the SM is found for mH≃120m_H \simeq 120 GeV using the observables most sensitive to mHm_H: AlA_l and mWm_W. In particular, quantum corrections, as predicted by the SM, are observed with a statistical significance of forty-four standard deviations. However, apparent deviations from the SM of 3.7σ\sigma and 2.8σ\sigma are found for the ZΜΜˉ\nu \bar{\nu} and right-handed Zbbˉ\bar{{\rm b}} couplings respectively. The maximum confidence level for agreement with the SM of the entire data set considered is ≃0.006\simeq 0.006 for mH≃180m_H \simeq 180 GeV. The reason why confidence levels about an order of magnitude higher than this have been claimed for global fits to similar data sets is explained.Comment: 47 pages, 8 figures, 24 tables. An in-depth study of statistical issues related to the comparison of precision EW data to the S

    Corrections to Quark Asymmetries at LEP

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    The most precise measurement of the weak mixing angle sin^2(theta) at LEP is from the forward-backward asymmetry e+e- --> bbbar at the Z-pole. In this note the QED and electroweak radiative corrections to obtain the pole asymmetry from the measured asymmetry for b- and c-quarks have been calculated using ZFITTER, which has been amended to allow a consistent treatment of partial two-loop corrections for the b-quark final asymmetries. A total correction of dAfbb=0.0019+/-0.0002 and dAfbc=0.0064+/-0.0001 has been found, where the remaining theoretical uncertainty is much too small to explain the apparent discrepancy between sin^2(theta) obtained from Afbb and from the left-right asymmetry at SLD

    Application of the Two-Scale Model to the HERMES Data on Nuclear Attenuation

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    The Two-Scale Model and its improved version were used to perform the fit to the HERMES data for Îœ\nu (the virtual photon energy) and z (the fraction of Îœ\nu carried by hadron) dependencies of nuclear multiplicity ratios for π+\pi^+ and π−\pi^- mesons electro-produced on two nuclear targets (14^{14}N and 84^{84}Kr). The quantitative criterium χ2\chi ^2 was used for the first time to analyse the results of the model fit to the nuclear multiplicity ratios data. The two-parameter's fit gives satisfactory agreement with the HERMES data. Best values of the parameters were then used to calculate the Îœ\nu- and zz - dependencies of nuclear attenuation for π0\pi^0, K+^+, K−^- and pˉ\bar{p} produced on 84^{84}Kr target, and also make a predictions for Îœ\nu, z and the Q2^2 (the photon virtuality) - dependencies of nuclear attenuation data for those identified hadrons and nuclea, that will be published by HERMES

    Band-specific phase engineering for curving and focusing light in waveguide arrays

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    Band specific design of curved light caustics and focusing in optical waveguide arrays is introduced. Going beyond the discrete, tight-binding model, which we examined recently, we show how the exact band structure and the associated diffraction relations of a periodic waveguide lattice can be exploited to phase-engineer caustics with predetermined convex trajectories or to achieve optimum aberration-free focal spots. We numerically demonstrate the formation of convex caustics involving the excitation of Floquet-Bloch modes within the first or the second band and even multi-band caustics created by the simultaneous excitation of more than one bands. Interference of caustics in abruptly autofocusing or collision scenarios are also examined. The experimental implementation of these ideas should be straightforward since the required input conditions involve phase-only modulation of otherwise simple optical wavefronts. By direct extension to more complex periodic lattices, possibilities open up for band specific curving and focusing of light inside 2D or even 3D photonic crystals

    A statistical study of the triple-link model in the synoptic problem

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    In New Testament studies, the synoptic problem is concerned with the relationships among the gospels of Matthew, Mark and Luke. In the present paper a careful specification in probabilistic terms is set up of what is known as the triple-link model, and, as a special case, the double-link model. Counts of the numbers of verbal agreements among the gospels are examined to investigate which of the possible triple-link models appears to give the best fit to the data

    Inflection and Derivation in a Second Language

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    Home economics research impacts: framework for evaluation

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    G 207-9 and LP 133-144: light curve analysis and asteroseismology of two ZZ Ceti stars

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    G 207-9 and LP 133-144 are two rarely observed ZZ Ceti stars located in the middle and close to the blue edge of the ZZ Ceti instability domain, respectively. We aimed to observe them at least during one observing season at Konkoly Observatory with the purpose of extending the list of known pulsation modes for asteroseismic investigations and detect any significant changes in their pulsational behaviour. We determined five and three new normal modes of G 207-9 and LP 133-144, respectively. In LP 133-144, our frequency analysis also revealed that at least at three modes there are actually triplets with frequency separations of ~4 microHz. The rotational period of LP 133-144 based on the triplets is ~42 h. The preliminary asteroseismic fits of G 207-9 predict Teff=12 000 or 12 400 K and M*=0.855-0.870 MSun values for the effective temperature and mass of the star, depending on the assumptions on the spherical degree (l) values of the modes. These results are in agreement with the spectroscopic determinations. In the case of LP 133-144, the best-fitting models prefer Teff=11 800 K in effective temperature and M*>=0.71 MSun stellar masses, which are more than 0.1 MSun larger than the spectroscopic value.Comment: 12 pages, 11 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society (2016 June 30
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