899 research outputs found
Multiple Scales in Pati-Salam Unification Models
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
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
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
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
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
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
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
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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