13,505 research outputs found
Pion form factor in large QCD
The electromagnetic form factor of the pion is obtained using a particular
realization of QCD in the large limit, which sums up the infinite number
of zero-width resonances to yield an Euler's Beta function of the Veneziano
type. This form factor agrees with space-like data much better than single
rho-meson dominance. A simple unitarization ansatz is illustrated, and the
resulting vector spectral function in the time-like region is shown to be in
reasonable agreement with the ALEPH data from threshold up to about 1.3
.Comment: Plain Latex, 9 pages, 2 figure
Corrections to the Gell-Mann-Oakes-Renner relation and chiral couplings and
Next to leading order corrections to the
Gell-Mann-Oakes-Renner relation (GMOR) are obtained using weighted QCD Finite
Energy Sum Rules (FESR) involving the pseudoscalar current correlator. Two
types of integration kernels in the FESR are used to suppress the contribution
of the kaon radial excitations to the hadronic spectral function, one with
local and the other with global constraints. The result for the pseudoscalar
current correlator at zero momentum is , leading to the chiral corrections to GMOR: . The resulting uncertainties are mostly due to variations in the upper
limit of integration in the FESR, within the stability regions, and to a much
lesser extent due to the uncertainties in the strong coupling and the strange
quark mass. Higher order quark mass corrections, vacuum condensates, and the
hadronic resonance sector play a negligible role in this determination. These
results confirm an independent determination from chiral perturbation theory
giving also very large corrections, i.e. roughly an order of magnitude larger
than the corresponding corrections in chiral . Combining
these results with our previous determination of the corrections to GMOR in
chiral , , we are able to determine two low
energy constants of chiral perturbation theory, i.e. , and , both at the
scale of the -meson mass.Comment: Revised version with minor correction
An optimal Q-state neural network using mutual information
Starting from the mutual information we present a method in order to find a
hamiltonian for a fully connected neural network model with an arbitrary,
finite number of neuron states, Q. For small initial correlations between the
neurons and the patterns it leads to optimal retrieval performance. For binary
neurons, Q=2, and biased patterns we recover the Hopfield model. For
three-state neurons, Q=3, we find back the recently introduced
Blume-Emery-Griffiths network hamiltonian. We derive its phase diagram and
compare it with those of related three-state models. We find that the retrieval
region is the largest.Comment: 8 pages, 1 figur
The more they’re beaten the better they be : Gendered Violence and Abuse in Victorian Laws and Literature
During the Victorian age, the law and society were in conversation with each other, and the law reflected Victorian gender norms. Nineteenth-century gender attitudes intersected with the law, medical discourse, and social customs in a multitude of ways. Abuse and gender violence occurred beneath the veneer of Victorian respectability. The models of nineteenth-century social conduct were highly gendered and placed men and women in separate social spheres. As this research indicates, the lived practices of Victorians, across social and economic strata, deviated from these accepted models of behavior. This thesis explores the ways that accepted and unaccepted standards of female behavior manifest in Victorian legal discourse and literary sources. The three tropes of female behavior analyzed in this thesis are: “the angel in the house,” “the mad woman,” and “the fallen woman.” Victorian men repeatedly failed to protect their wives, daughters, and companions and were often the sources of abuse and violence. Women, in turn, were unable to shape themselves to fit the accepted model of Victorian womanhood. This thesis suggests that widespread Victorian gender attitudes and social causes that are taken up by politicians are reflected in the legal system. This thesis unearths the voices of Victorian women, both literary and historical ones, in order to tell their stories and analyze the ways that their experiences are a result of social conventions and legal standards of the nineteenth-century
UH-60A Airloads Flight Test Program: Data Counter 9017
Aeromechanics Branch interns at Ames Research Center have been directly contributing to the data quality analysis and reporting of the UH-60A Airloads Flight Test Program for many years. In chronological order (together with the semester and year): Caroline Edwards (Summer 2011); Joni DeGuzman and Carson Turner (Fall 2011); Eric Fritz (Spring 2012); Connor Beierle (Fall 2012); Christopher Olinger (Spring and Summer 2013); Needa Lin, Anatole Levkoff, Maxwell Loebig, Jose Orejel, Megan Prout, and Albert Sue (Summer 2014); Jared Archey (Fall 2014); Alexander Crone (Summer 2015); Jeffrey Diament, Austin Djang, and Jessica Swan (Summer 2016); Makenzie Allen (Summer 2017); Colin Lauzon (Fall 2017); Eric Gilkey (Spring 2018); and Nicholas Masso (Summer 2019). These interns have spent their internships reviewing flight logs, extracting the data out of TRENDS, formatting the data into spreadsheets, writing code to automate the process, and plotting results. Without their efforts, much of the work would be unfinished. The authors appreciate the achievements of the UH-60A Airloads Working Group during its 20-year lifetime, as well the contributions of Randy Peterson, Tom Norman, and William Warmbrodt to the data processing and assistance with the report preparation. Lastly, this report is dedicated to William Bousman for his efforts preceding, during, and subsequent to the UH-60A Airloads Flight Test Program
Chiral corrections to the Gell-Mann-Oakes-Renner relation
The next to leading order chiral corrections to the
Gell-Mann-Oakes-Renner (GMOR) relation are obtained using the pseudoscalar
correlator to five-loop order in perturbative QCD, together with new finite
energy sum rules (FESR) incorporating polynomial, Legendre type, integration
kernels. The purpose of these kernels is to suppress hadronic contributions in
the region where they are least known. This reduces considerably the systematic
uncertainties arising from the lack of direct experimental information on the
hadronic resonance spectral function. Three different methods are used to
compute the FESR contour integral in the complex energy (squared) s-plane, i.e.
Fixed Order Perturbation Theory, Contour Improved Perturbation Theory, and a
fixed renormalization scale scheme. We obtain for the corrections to the GMOR
relation, , the value . This result
is substantially more accurate than previous determinations based on QCD sum
rules; it is also more reliable as it is basically free of systematic
uncertainties. It implies a light quark condensate . As a byproduct, the chiral perturbation theory (unphysical) low energy
constant is predicted to be , or .Comment: A comment about the value of the strong coupling has been added at
the end of Section 4. No change in results or conslusion
Dynamical Critical Phenomena and Large Scale Structure of the Universe: the Power Spectrum for Density Fluctuations
As is well known, structure formation in the Universe at times after
decoupling can be described by hydrodynamic equations. These are shown here to
be equivalent to a generalization of the stochastic Kardar--Parisi--Zhang
equation with time-- dependent viscosity in epochs of dissipation. As a
consequence of the Dynamical Critical Scaling induced by noise and
fluctuations, these equations describe the fractal behavior (with a scale
dependent fractal dimension) observed at the smaller scales for the
galaxy--to--galaxy correlation function and the Harrison--Zel'dovich
spectrum at decoupling. By a Renormalization Group calculation of the
two--point correlation function between galaxies in the presence of (i) the
expansion of the Universe and (ii) non--equilibrium, we can account, from first
principles, for the main features of the observed shape of the power spectrum.Comment: 13 pages with 2 encapsulated PostScript figures included, gzipped tar
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