59,086 research outputs found
Fundamental Constant Observational Bounds on the Variability of the QCD Scale
Many physical theories beyond the Standard Model predict time variations of
basic physics parameters. Direct measurement of the time variations of these
parameters is very difficult or impossible to achieve. By contrast,
measurements of fundamental constants are relatively easy to achieve, both in
the laboratory and by astronomical spectra of atoms and molecules in the early
universe. In this work measurements of the proton to electron mass ratio
and the fine structure constant are combined to place mildly model
dependent limits on the fractional variation of the Quantum Chromodynamic Scale
and the sum of the fractional variations of the Higgs Vacuum Expectation Value
and the Yukawa couplings on time scales of more than half the age of the
universe. The addition of another model parameter allows the fractional
variation of the Higgs VEV and the Yukawa couplings to be computed separately.
Limits on their variation are found at the level of less than over the past seven gigayears. A model dependent relation between the
expected fractional variation of relative to tightens the limits
to over the same time span. Limits on the present day rate of change
of the constants and parameters are then calculated using slow roll
quintessence. A primary result of this work is that studies of the
dimensionless fundamental constants such as and , whose values
depend on the values of the physics parameters, are excellent monitors of the
limits on the time variation of these parameters.Comment: Accepted for publication in the Monthly Notices of the Royal
Astronomical Society, 8 pages, 5 figure
Andrew I. Thompson - From Tragedy to Policy: Representations of Muslims and Islam in U.S. Mainstream Media
Following the terrorist attacks of September 11th came a flood of criticism of Islam and Muslims in the U.S. media. Many saw Islam as the root cause of the attacks, but failed to assess the political or social issues in the Middle East, or even the United Statesâ role in the region. An example of this is the New York Timesâ section that ran immediately after the attacks entitled âA Nation Challenged,â which included titles such as: âYes, this is about Islam,â âThis is a religious war,â âBarbarians at the gate,â and âThe one true faith.â This project analyzes the mainstream print mediaâsâNew York Times, Wall Street Journal, Time, and USA Todayârepresentation of Muslims and Islam from September 11, 2001 to December 31, 2001 and its relation to U.S. foreign policy. My assertion is that the mainstream media employed rhetorical emulating, and sometimes mimicking, of Samuel Huntingtonâs Clash of Civilizations theory when representing Muslims and Islam, which in turn supported aggressive military action in the Iraq and Afghanistan wars. In support of my assertion, I find that Huntingtonâs clash of civilizations absolves the US of all guilt regarding the attacks. Once the theory is adopted it becomes a given, something intrinsic to politics, thus making the âclashâ seem inevitable. The Clash of Civilizations theory also supports aggressive military action because of the implicit and explicit denunciation of all âcivilizationsâ that are not âWestern.âhttps://epublications.marquette.edu/mcnair_2013/1016/thumbnail.jp
Confronting Cosmology and New Physics with Fundamental Constants
The values of the fundamental constants such as , the proton
to electron mass ratio and , the fine structure constant, are sensitive
to the product where is a coupling constant
between a rolling scalar field responsible for the acceleration of the
expansion of the universe and the electromagnetic field with x standing for
either or . The dark energy equation of state can assume
values different than in cosmologies where the acceleration of the
expansion is due to a scalar field. In this case the value of both and
changes with time. The values of the fundamental constants, therefore,
monitor the equation of state and are a valuable tool for determining as a
function of redshift. In fact the rolling of the fundamental constants is one
of the few definitive discriminators between acceleration due to a cosmological
constant and acceleration due to a quintessence rolling scalar field. is
often given in parameterized form for comparison with observations. In this
manuscript the predicted evolution of , is calculated for a range of
parameterized equation of state models and compared to the observational
constraints on . We find that the current limits on place significant constraints on linear equation of state models and
on thawing models where deviates from at late times. They also
constrain non-dynamical models that have a constant not equal to .
These constraints are an important compliment to geometric tests of in that
geometric tests are sensitive to the evolution of the universe before the epoch
of observation while fundamental constants are sensitive to the evolution of
the universe after the observational epoch. Abstract truncated.Comment: To appear in the conference proceedings of the Sesto Conference on
Fundamental Constants and Coupling
The Relation Between Fundamental Constants and Particle Physics Parameters
The observed constraints on the variability of the proton to electron mass
ratio and the fine structure constant are used to establish
constraints on the variability of the Quantum Chromodynamic Scale and a
combination of the Higgs Vacuum Expectation Value and the Yukawa couplings.
Further model dependent assumptions provide constraints on the Higgs VEV and
the Yukawa couplings separately. A primary conclusion is that limits on the
variability of dimensionless fundamental constants such as and
provide important constraints on the parameter space of new physics and
cosmologies.Comment: Published in the proceedings of the Conference on Varying Constants
and Fundamental Cosmology VARCOSMOFUN16. Modified from the Universe style to
process properly in arXi
Beta Function Quintessence Cosmological Parameters and Fundamental Constants I: Power and Inverse Power Law Dark Energy Potentials
This investigation explores using the beta function formalism to calculate
analytic solutions for the observable parameters in rolling scalar field
cosmologies. The beta function in this case is the derivative of the scalar
with respect to the natural log of the scale factor ,
. Once the beta function is specified,
modulo a boundary condition, the evolution of the scalar as a function
of the scale factor is completely determined. A rolling scalar field cosmology
is defined by its action which can contain a range of physically motivated dark
energy potentials. The beta function is chosen so that the associated "beta
potential" is an accurate, but not exact, representation of the appropriate
dark energy model potential. The basic concept is that the action with the beta
potential is so similar to the action with the model potential that solutions
using the beta action are accurate representations of solutions using the model
action. The beta function provides an extra equation to calculate analytic
functions of the cosmologies parameters as a function of the scale factor that
are that are not calculable using only the model action. As an example this
investigation uses a quintessence cosmology to demonstrate the method for power
and inverse power law dark energy potentials. An interesting result of the
investigation is that the Hubble parameter H is almost completely insensitive
to the power of the potentials and that CDM is part of the family of
quintessence cosmology power law potentials with a power of zero.Comment: Accepted for publication by the Monthly Notices of the Royal
Astronomical Societ
Scattering by a semi-infinite lattice and the excitation of Bloch waves
The interaction of a time-harmonic plane wave with a semi-infinite lattice of identical circular cylinders is considered. No assumptions about the radius of the cylinders, or their scattering properties, are made. Multipole expansions and Grafâs addition theorem are used to reduce the boundary value problem to an infinite linear system of equations. Applying the z transform and disregarding interaction effects due to certain strongly damped modes then leads to a matrix WienerâHopf equation with rational elements. This is solved by a straightforward method that does not require matrix factorisation. Implementation of the method requires that the zeros of the matrix determinant be located numerically, and once this is achieved, all far field quantities can be calculated. Numerical results that show the proportion of energy reflected back from the edge are presented for several different lattice geometries. 1
Spinning in the NAPLAN ether: 'Postscript on the control societies' and the seduction of education in Australia
This paper applies concepts Deleuze developed in his âPostscript on the Societies of Controlâ, especially those relating to modulatory power, dividuation and control, to aspects of Australian schooling to explore how this transition is manifesting itself. Two modulatory machines of assessment, NAPLAN and My Schools, are examined as a means to better understand how the disciplinary institution is changing as a result of modulation. This transition from discipline to modulation is visible in the declining importance of the disciplinary teacher/student relationship as a measure of the success of the educative process. The transition occurs through seduction because that which purports to measure classroom quality is in fact a serpent of modulation that produces simulacra of the disciplinary classroom. The effect is to sever what happens in the disciplinary space from its representations in a luminiferous ether that overlays the classroom
E2 component in subcoulomb breakup of ^{8}B
We calculate the angular distribution and total cross section of the ^{7}Be
fragment emitted in the break up reaction of ^{8}B on ^{58}Ni and ^{208}Pb
targets at the subCoulomb beam energy of 25.8 MeV, within the non-relativistic
theory of Coulomb excitation with proper three-body kinematics. The relative
contributions of the E1, E2 and M1 multipolarities to the cross sections are
determined. The E2 component makes up about 65% and 40% of the ^{7}Be total
cross section for the ^{58}Ni and ^{208}Pb targets respectively. We find that
the extraction of the astrophysical S-factor, S_{17}(0), for the
^{7}Be(p,\gamma)^8B reaction at solar energies from the measurements of the
cross sections of the ^{7}Be fragment in the Coulomb dissociation of ^{8}B at
sub-Coulomb energies is still not free from the uncertainties of the E2
component.Comment: Revised version (correcting earlier errors) submitted to Phys. Letts.
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