4,146 research outputs found
A Solution of the Strong CP Problem Transforming the theta-angle to the KM CP-violating Phase
It is shown that in the scheme with a rotating fermion mass matrix (i.e. one
with a scale-dependent orientation in generation space) suggested earlier for
explaining fermion mixing and mass hierarchy, the theta-angle term in the QCD
action of topological origin can be eliminated by chiral transformations, while
giving still nonzero masses to all quarks. Instead, the effects of such
transformations get transmitted by the rotation to the CKM matrix as the KM
phase giving, for of order unity, a Jarlskog invariant typically of
order as experimentally observed. Strong and weak CP violations
appear then as just two facets of the same phenomenon.Comment: 14 pages, 2 figure
Quantum Key Distribution
This chapter describes the application of lasers, specifically diode lasers,
in the area of quantum key distribution (QKD). First, we motivate the
distribution of cryptographic keys based on quantum physical properties of
light, give a brief introduction to QKD assuming the reader has no or very
little knowledge about cryptography, and briefly present the state-of-the-art
of QKD. In the second half of the chapter we describe, as an example of a
real-world QKD system, the system deployed between the University of Calgary
and SAIT Polytechnic. We conclude the chapter with a brief discussion of
quantum networks and future steps.Comment: 20 pages, 12 figure
New Angle on the Strong CP and Chiral Symmetry Problems from a Rotating Mass Matrix
It is shown that when the mass matrix changes in orientation (rotates) in
generation space for changing energy scale, then the masses of the lower
generations are not given just by its eigenvalues. In particular, these masses
need not be zero even when the eigenvalues are zero. In that case, the strong
CP problem can be avoided by removing the unwanted term by a chiral
transformation in no contradiction with the nonvanishing quark masses
experimentally observed. Similarly, a rotating mass matrix may shed new light
on the problem of chiral symmetry breaking. That the fermion mass matrix may so
rotate with scale has been suggested before as a possible explanation for
up-down fermion mixing and fermion mass hierarchy, giving results in good
agreement with experiment.Comment: 14 page
Updates to the Dualized Standard Model on Fermion Masses and Mixings
The Dualized Standard Model has scored a number of successes in explaining
the fermion mass hierarchy and mixing pattern. This note contains updates to
those results including (a) an improved treatment of neutrino oscillation free
from previous assumptions on neutrino masses, and hence admitting now the
preferred LMA solution to solar neutrinos, (b) an understanding of the
limitation of the 1-loop calculation so far performed, thus explaining the two
previous discrepancies with data, and (c) an analytic derivation and
confirmation of the numerical results previously obtained.Comment: 15 pages, Latex, 1 figure using ep
Lagrangian bias in the local bias model
It is often assumed that the halo-patch fluctuation field can be written as a
Taylor series in the initial Lagrangian dark matter density fluctuation field.
We show that if this Lagrangian bias is local, and the initial conditions are
Gaussian, then the two-point cross-correlation between halos and mass should be
linearly proportional to the mass-mass auto-correlation function. This
statement is exact and valid on all scales; there are no higher order
contributions, e.g., from terms proportional to products or convolutions of
two-point functions, which one might have thought would appear upon truncating
the Taylor series of the halo bias function. In addition, the auto-correlation
function of locally biased tracers can be written as a Taylor series in the
auto-correlation function of the mass; there are no terms involving, e.g.,
derivatives or convolutions. Moreover, although the leading order coefficient,
the linear bias factor of the auto-correlation function is just the square of
that for the cross-correlation, it is the same as that obtained from expanding
the mean number of halos as a function of the local density only in the
large-scale limit. In principle, these relations allow simple tests of whether
or not halo bias is indeed local in Lagrangian space. We discuss why things are
more complicated in practice. We also discuss our results in light of recent
work on the renormalizability of halo bias, demonstrating that it is better to
renormalize than not. We use the Lognormal model to illustrate many of our
findings.Comment: 14 pages, published on JCA
Simulation, visualization and dosimetric validation of scatter radiation distribution under fluoroscopy settings
2015-2016 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe
In vitro expressed dystrophin fragments do not associate with each other
AbstractDystrophin, a component of the muscle membrane cytoskeleton, is the protein altered in Duchenne Muscular Dystrophy (DMD) and Becker Muscular Dystrophy (BMD). Dystrophin shares significant homology with other cytoskeletal proteins, such as α-actinin and spectrin. On the basis of its sequence similarity with α-actinin and spectrin, dystrophin has been proposed to function as dimer. However, the existence of both dimers and monomers have been observed by electron microscopy. To address this apparent discrepancy, we expressed dystrophin fragments composed of different domains in an in vitro translation system. The expressed fragments were tested for their ability to interact with each other and full-length dystrophin by both immunoprecipitation and blot overlay assays. These assays were successfully used to demonstrate the dimerization of α-actinin and spectrin, yet failed to detect any interaction between dystrophin fragments. Although these in vitro results do not prove that dystrophin is not a dimer in vivo, they do indicate that this interaction is not like that of the α-actinin and spectrin
- …