899 research outputs found

    Multiple Scales in Pati-Salam Unification Models

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    We investigate models where gauge unification (GUT) proceeds in steps that include Pati-Salam symmetry. Beyond the Standard Model, we allow for a well-defined set of small representations of the GUT gauge group. We show that all possible chains of Pati-Salam symmetry breaking can be realized in accordance with gauge-coupling unification. We identify, in particular, models with unification near the Planck scale, with intermediate left-right or SU(4) quark-lepton symmetries that are relevant for flavor physics, with new colored particles at accessible energies, and with an enlarged electroweak Higgs sector. We look both at supersymmetric and non-supersymmetric scenarios.Comment: 48 pages, 11 figures, version accepted for publication in JHE

    Renormalized Soft-Higgs Theorems

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    The Higgs couplings to matter fields are proportional to their masses. Thus Higgs amplitudes can be obtained by differentiating amplitudes without Higgs with respect to masses. We show how this well-known statement can be extended to higher order when renormalization effects are taken into account. We establish the connection with the Callan-Symanzik and renormalization group equations and consider also pseudoscalar Higgs couplings to fermions. Furthermore, we address the case where the Higgs couples to a heavy particle that is integrated out from the low-energy effective Lagrangian. We derive effective interactions where mass logarithms are resummed by renormalization-group methods, and give expansions of the results up to next-to-leading order.Comment: 21 pages LaTeX2e, 3 figures (generated automatically using the LaTeX package feynmf, or from the appended uuencoded file

    Combining Pati-Salam and Flavour Symmetries

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    We construct an extension of the Standard Model (SM) which is based on grand unification with Pati-Salam symmetry. The setup is supplemented with the idea of spontaneous flavour symmetry breaking which is mediated through flavon fields with renormalizable couplings to new heavy fermions. While we argue that the new gauge bosons in this approach can be sufficiently heavy to be irrelevant at low energies, the fermionic partners of the SM quarks, in particular those for the third generation, can be relatively light and provide new sources of flavour violation. The size of the effects is constrained by the observed values of the SM Yukawa matrices, but in a way that is different from the standard minimal-flavour violation approach. We determine characteristic deviations from the SM that could eventually be observed in future precision measurements.Comment: 26 pages, 5 figure

    Unimagined Imaginary Parts in Heavy Quark Effective Field Theory

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    We argue that the imaginary parts of the anomalous dimensions in the multiparticle sectors of heavy quark effective field theory may be removed by a suitable redefinition of the multiparticle states. The connection between the imaginary parts of the anomalous dimensions and the interquark potential is pointed outComment: 14 Pages, LaTeX, HUTP-93/A009, IKDA 93/

    TuLiPA : towards a multi-formalism parsing environment for grammar engineering

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    In this paper, we present an open-source parsing environment (TĂĽbingen Linguistic Parsing Architecture, TuLiPA) which uses Range Concatenation Grammar (RCG) as a pivot formalism, thus opening the way to the parsing of several mildly context-sensitive formalisms. This environment currently supports tree-based grammars (namely Tree-Adjoining Grammars (TAG) and Multi-Component Tree-Adjoining Grammars with Tree Tuples (TT-MCTAG)) and allows computation not only of syntactic structures, but also of the corresponding semantic representations. It is used for the development of a tree-based grammar for German

    TuLiPA : towards a multi-formalism parsing environment for grammar engineering

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    In this paper, we present an open-source parsing environment (TĂĽbingen Linguistic Parsing Architecture, TuLiPA) which uses Range Concatenation Grammar (RCG) as a pivot formalism, thus opening the way to the parsing of several mildly context-sensitive formalisms. This environment currently supports tree-based grammars (namely Tree-Adjoining Grammars (TAG) and Multi-Component Tree-Adjoining Grammars with Tree Tuples (TT-MCTAG)) and allows computation not only of syntactic structures, but also of the corresponding semantic representations. It is used for the development of a tree-based grammar for German

    Adaptive Sensor Data Acquisition for Gait Analysis

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    AbstractIn this paper a method is presented that uses one sensor configuration for both static and dynamic loading conditions to capture plantar pressure distribution values. In the gait analysis, different phases are from interest. The phases produces highly different signals and with conventional sensors and static data acquisition systems it is often difficult to achieve high precision measure- ments. An advanced programmable amplifier can be used to adapt the full resolution of the measurement system dynamically to the needs of the gait analyses. With the proposed system, it is possible to precisely measure the gait phases without changing any hardware. While the system is performing it is energy efficient as it only consumes power if needed. Furthermore, it is highly integrated and space saving. Thus, ideally suited for mobile outdoor applications. The technology used in this example can be applied to many different general sensor measurement questions in sports engineering

    Resonances and Unitarity in Weak Boson Scattering at the LHC

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    A crucial test of the Standard Model is the measurement of electroweak gauge-boson scattering. In this paper, we describe a generic parameterization aimed at a realistic simulation of weak-boson scattering at the LHC. The parameterization implements resonances of all possible spin and isospin combinations, properly matched to the low-energy effective (chiral) Lagrangian, includes leading higher-order effects and contains a minimal unitarization scheme. We implement the parameterization in the Monte-Carlo event generator WHIZARD and present results for complete partonic cross-section integration and event generation. We provide a comparison with the effective W approximation that previously has been used for most WW scattering studies at hadron colliders.Comment: 49 pages, 15 figure
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