1,267 research outputs found
Investigating the Design, Construction, and Performance of a π\u3csup\u3e0\u3c/sup\u3e Spectrometer
A π0 spectrometer constructed at the Los Alamos Meson Physics Facility in 1977 by H. W. Baer is investigated using a historical and physical approach. A history is given of the spectrometer, including the circumstances which gave rise to its construction and its eventually decommissioning. This is supported by a theoretical description of the spectrometer operation, as well as current Monte Carlo simulations which aimed to reproduce the behavior of the original π0 spectrometer
21st Century Simulation: Exploiting High Performance Computing and Data Analysis
This paper identifies, defines, and analyzes the limitations imposed on Modeling and Simulation by outmoded
paradigms in computer utilization and data analysis. The authors then discuss two emerging capabilities to
overcome these limitations: High Performance Parallel Computing and Advanced Data Analysis. First, parallel
computing, in supercomputers and Linux clusters, has proven effective by providing users an advantage in
computing power. This has been characterized as a ten-year lead over the use of single-processor computers.
Second, advanced data analysis techniques are both necessitated and enabled by this leap in computing power.
JFCOM's JESPP project is one of the few simulation initiatives to effectively embrace these concepts. The
challenges facing the defense analyst today have grown to include the need to consider operations among non-combatant
populations, to focus on impacts to civilian infrastructure, to differentiate combatants from non-combatants,
and to understand non-linear, asymmetric warfare. These requirements stretch both current
computational techniques and data analysis methodologies. In this paper, documented examples and potential
solutions will be advanced. The authors discuss the paths to successful implementation based on their experience.
Reviewed technologies include parallel computing, cluster computing, grid computing, data logging, OpsResearch,
database advances, data mining, evolutionary computing, genetic algorithms, and Monte Carlo sensitivity analyses.
The modeling and simulation community has significant potential to provide more opportunities for training and
analysis. Simulations must include increasingly sophisticated environments, better emulations of foes, and more
realistic civilian populations. Overcoming the implementation challenges will produce dramatically better insights,
for trainees and analysts. High Performance Parallel Computing and Advanced Data Analysis promise increased
understanding of future vulnerabilities to help avoid unneeded mission failures and unacceptable personnel losses.
The authors set forth road maps for rapid prototyping and adoption of advanced capabilities. They discuss the
beneficial impact of embracing these technologies, as well as risk mitigation required to ensure success
Implications of Low Energy Supersymmetry Breaking at the Tevatron
The signatures for low energy supersymmetry breaking at the Tevatron are
investigated. It is natural that the lightest standard model superpartner is an
electroweak neutralino, which decays to an essentially massless Goldstino and
photon, possibly within the detector. In the simplest models of gauge-mediated
supersymmetry breaking, the production of right-handed sleptons, neutralinos,
and charginos leads to a pair of hard photons accompanied by leptons and/or
jets with missing transverse energy. The relatively hard leptons and softer
photons of the single e^+e^- \gamma \gamma + \EmissT event observed by CDF
implies this event is best interpreted as arising from left-handed slepton pair
production. In this case the rates for l^{\pm} \gamma \gamma + \EmissT and
\gamma \gamma + \EmissT are comparable to that for l^+l^- \gamma \gamma +
\EmissT.Comment: 18 pages, Latex, tables correcte
Investigación sobre celdas solares de película delgada orgánica en la Universidad de Stanford
La serie de 2 artículos que llevan como título “Organic Thin-Film Solar Cell Research Conducted at Stanford University”, es una traducción autorizada por sus autores:Gary C. Bjorklund, y Thomas M. Baer, en Stanford Photonics Research Center.Esta serie se encuentra publicada en PHOTONICS SPECTRA, de noviembre de 2007, volumen 41-11 y diciembre de 2007 , volumen 41-12, respectivamente. Los autores plantean la urgente necesidad de colectivizar sus hallazgos con el fin de permitir el conocimiento de los mismos, de modo que esto pueda llegar a ser un incentivo para quienes investigan y pretendan utilizar energías renovables, reducir la contaminación ambiental y contribuir a la disminución de emisiones perjudiciales al ambiente, por el uso implacable de productos contaminantes. Entornos publica los dos artículos integrados en la presente edición, como parte I y parte II
Report of the Supersymmetry Theory Working Group
We provide a mini-guide to some of the possible manifestations of weak scale
supersymmetry. For each of six scenarios we provide a brief description of the
theoretical underpinnings, the adjustable parameters, a qualitative description
of the associated phenomenology at future colliders, comments on how to
simulate each scenario with existing event generators.Comment: Report of Snowmass Supersymmetry Theory Working Group; 14 pages plus
3 figures using latex2e and snow2e.cls; this version has corrected a number
of typos from the first versio
How Do We Combat Bogus Medicines in the Age of the COVID-19 Pandemic?
The COVID-19 pandemic has brought concurrent challenges. The increased incidence of fake and falsified product distribution is one of these problems with tremendous impact, especially in low- and middle-income countries. Up to a tenth of medicines including antibiotics and antimalarial drugs in the African market are considered falsified. Pandemics make this worse by creating an ecosystem of confusion, distraction, and vulnerability stemming from the pandemic as health systems become more stressed and the workload of individuals increased. These environments create opportunities for substandard and falsified medicines to be more easily introduced into the marketplace by unscrupulous operators. In this work, we discussed some of the challenges with fake or falsified product distribution in the context of COVID-19 and proposed strategies to best manage this problem
Light Sneutrino Dark Matter at the LHC
In supersymmetric (SUSY) models with Dirac neutrino masses, a weak-scale
trilinear A-term that is not proportional to the small neutrino Yukawa
couplings can induce a sizable mixing between left and right-handed sneutrinos.
The lighter sneutrino mass eigenstate can hence become the lightest SUSY
particle (LSP) and a viable dark matter candidate. In particular, it can be an
excellent candidate for light dark matter with mass below ~10 GeV. Such a light
mixed sneutrino LSP has a dramatic effect on SUSY signatures at the LHC, as
charginos decay dominantly into the light sneutrino plus a charged lepton, and
neutralinos decay invisibly to a neutrino plus a sneutrino. We perform a
detailed study of the LHC potential to resolve the light sneutrino dark matter
scenario by means of three representative benchmark points with different
gluino and squark mass hierarchies. We study in particular the determination of
the LSP (sneutrino) mass from cascade decays involving charginos, using the mT2
variable. Moreover, we address measurements of additional invisible sparticles,
in our case the lightest neutralino, and the question of discrimination against
the MSSM.Comment: 25 pages, 16 figure
WMAP-Compliant Benchmark Surfaces for MSSM Higgs Bosons
We explore `benchmark surfaces' suitable for studying the phenomenology of
Higgs bosons in the minimal supersymmetric extension of the Standard Model
(MSSM), which are chosen so that the supersymmetric relic density is generally
compatible with the range of cold dark matter density preferred by WMAP and
other observations. These benchmark surfaces are specified assuming that
gaugino masses m_{1/2}, soft trilinear supersymmetry-breaking parameters A_0
and the soft supersymmetry-breaking contributions m_0 to the squark and slepton
masses are universal, but not those associated with the Higgs multiplets (the
NUHM framework). The benchmark surfaces may be presented as M_A-tan_beta planes
with fixed or systematically varying values of the other NUHM parameters, such
as m_0, m_{1/2}, A_0 and the Higgs mixing parameter mu. We discuss the
prospects for probing experimentally these benchmark surfaces at the Tevatron
collider, the LHC, the ILC, in B physics and in direct dark-matter detection
experiments. An Appendix documents developments in the FeynHiggs code that
enable the user to explore for her/himself the WMAP-compliant benchmark
surfaces.Comment: Minor corrections, references added. 43 pages, 10 figures. Version to
appear in JHE
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