27,133 research outputs found
On R-duals and the duality principle in Gabor analysis
The concept of R-duals of a frame was introduced by Casazza, Kutyniok and
Lammers in 2004, with the motivation to obtain a general version of the duality
principle in Gabor analysis. For tight Gabor frames and Gabor Riesz bases the
three authors were actually able to show that the duality principle is a
special case of general results for R-duals. In this paper we introduce various
alternative R-duals, with focus on what we call R-duals of type II and III. We
show how they are related and provide characterizations of the R-duals of type
II and III. In particular, we prove that for tight frames these classes
coincide with the R-duals by Casazza et el., which is desirable in the sense
that the motivating case of tight Gabor frames already is well covered by these
R-duals. On the other hand, all the introduced types of R-duals generalize the
duality principle for larger classes of Gabor frames than just the tight frames
and the Riesz bases; in particular, the R-duals of type III cover the duality
principle for all Gabor frames
Deconstructed Higgsless Models at LHC: The Top Triangle Moose
We describe a deconstructed Higgsless model in which electroweak symmetry
breaking results largely from a Higgsless mechanism while the top quark mass is
generated by a topcolor mechanism. The top quark mass arises from a Yukawa
coupling to an effective top-Higgs which develops a small vacuum expectation
value. Both the heavy partners of the electoweak gauge bosons and those for the
SM fermions can be light enough to be visible at LHC.Comment: 5 pages, 3 figures; from the Proceedings of the 2010 Rencontres de
Bloi
The Top Triangle Moose
We introduce a deconstructed model that incorporates both Higgsless and
top-color mechanisms. The model alleviates the typical tension in Higgsless
models between obtaining the correct top quark mass and keeping delta-rho
small. It does so by singling out the top quark mass generation as arising from
a Yukawa coupling to an effective top-Higgs which develops a small vacuum
expectation value, while electroweak symmetry breaking results largely from a
Higgsless mechanism. As a result, the heavy partners of the SM fermions can be
light enough to be seen at the LHC.Comment: To appear in proceedings of SCGT09, Nagoya, Japan. 5 page
Electric Polarizability of Neutral Hadrons from Lattice QCD
By simulating a uniform electric field on a lattice and measuring the change
in the rest mass, we calculate the electric polarizability of neutral mesons
and baryons using the methods of quenched lattice QCD. Specifically, we measure
the electric polarizability coefficient from the quadratic response to the
electric field for 10 particles: the vector mesons and ; the
octet baryons n, , , , and ;
and the decouplet baryons , , and .
Independent calculations using two fermion actions were done for consistency
and comparison purposes. One calculation uses Wilson fermions with a lattice
spacing of fm. The other uses tadpole improved L\"usher-Weiss gauge
fields and clover quark action with a lattice spacing fm. Our results
for neutron electric polarizability are compared to experiment.Comment: 25 pages, 20 figure
Low-Energy Effective Theory, Unitarity, and Non-Decoupling Behavior in a Model with Heavy Higgs-Triplet Fields
We discuss the properties of a model incorporating both a scalar electroweak
Higgs doublet and an electroweak Higgs triplet. We construct the low-energy
effective theory for the light Higgs-doublet in the limit of small (but
nonzero) deviations in the rho parameter from one, a limit in which the triplet
states become heavy. For small deviations in the rho parameter from one,
perturbative unitarity of WW scattering breaks down at a scale inversely
proportional to the renormalized vacuum expectation value of the triplet field
(or, equivalently, inversely proportional to the square-root of the deviation
of the rho parameter from one). This result imposes an upper limit on the
mass-scale of the heavy triplet bosons in a perturbative theory; we show that
this upper bound is consistent with dimensional analysis in the low-energy
effective theory. Recent articles have shown that the triplet bosons do not
decouple, in the sense that deviations in the rho parameter from one do not
necessarily vanish at one-loop in the limit of large triplet mass. We clarify
that, despite the non-decoupling behavior of the Higgs-triplet, this model does
not violate the decoupling theorem since it incorporates a large dimensionful
coupling. Nonetheless, we show that if the triplet-Higgs boson masses are of
order the GUT scale, perturbative consistency of the theory requires the
(properly renormalized) Higgs-triplet vacuum expectation value to be so small
as to be irrelevant for electroweak phenomenology.Comment: Revtex, 11 pages, 7 eps figures included; references updated and
three footnotes adde
Power filtration of CMB observational data
We propose a power filter Gp for linear reconstruction of the CMB signal from
observational maps. This Gp filter preserves the power spectrum of the CMB
signal in contrast to the Wiener filter which diminishes the power spectrum of
the reconstructed CMB signal. We demonstrate how peak statistics and a cluster
analysis can be used to estimate the probability of the presence of a CMB
signal in observational records. The efficiency of the Gp filter is
demonstrated on a toy model of an observational record consisting of a CMB
signal and noise in the form of foreground point sources.Comment: 17 pages; 4 figures; submitted to International Journal of Modern
Physic
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