6,174 research outputs found
The CEDAR Project
We describe the plans and objectives of the CEDAR project (Combined e-Science
Data Analysis Resource for High Energy Physics) newly funded by the PPARC
e-Science programme in the UK. CEDAR will combine the strengths of the well
established and widely used HEPDATA database of HEP data and the innovative
JetWeb data/Monte Carlo comparison facility, built on the HZTOOL package, and
will exploit developing grid technology. The current status and future plans of
both of these individual sub-projects within the CEDAR framework are described,
showing how they will cohesively provide (a) an extensive archive of Reaction
Data, (b) validation and tuning of Monte Carlo programs against these reaction
data sets, and (c) a validated code repository for a wide range of HEP code
such as parton distribution functions and other calculation codes used by
particle physicists. Once established it is envisaged CEDAR will become an
important Grid tool used by LHC experimentalists in their analyses and may well
serve as a model in other branches of science where there is a need to compare
data and complex simulations.Comment: 4 pages, 4 postscript figures, uses CHEP2004.cls. Presented at
Computing in High-Energy Physics (CHEP'04), Interlaken, Switzerland, 27th
September - 1st October 200
Letter from J. Emory & B. Waugh to James B. Finley
John Emory and Beverly Waugh [book agents appointed to the Methodist Book Concern,1828-1832] send an invoice to Finley for $29.77. This account for subscriptions to the 1824 and 1825 Methodist Magazine is still open and needs to be closed. If someone else is responsible for payment, Emory and Waugh ask Finley to let them know. Abstract Number - 566https://digitalcommons.owu.edu/finley-letters/1862/thumbnail.jp
HepForge: A lightweight development environment for HEP software
Setting up the infrastructure to manage a software project can become a task
as significant writing the software itself. A variety of useful open source
tools are available, such as Web-based viewers for version control systems,
"wikis" for collaborative discussions and bug-tracking systems, but their use
in high-energy physics, outside large collaborations, is insubstantial.
Understandably, physicists would rather do physics than configure project
management tools.
We introduce the CEDAR HepForge system, which provides a lightweight
development environment for HEP software. Services available as part of
HepForge include the above-mentioned tools as well as mailing lists, shell
accounts, archiving of releases and low-maintenance Web space. HepForge also
exists to promote best-practice software development methods and to provide a
central repository for re-usable HEP software and phenomenology codes.Comment: 3 pages, 0 figures. To be published in proceedings of CHEP06. Refers
to the HepForge facility at http://hepforge.cedar.ac.u
HepData and JetWeb: HEP data archiving and model validation
The CEDAR collaboration is extending and combining the JetWeb and HepData
systems to provide a single service for tuning and validating models of
high-energy physics processes. The centrepiece of this activity is the fitting
by JetWeb of observables computed from Monte Carlo event generator events
against their experimentally determined distributions, as stored in HepData.
Caching the results of the JetWeb simulation and comparison stages provides a
single cumulative database of event generator tunings, fitted against a wide
range of experimental quantities. An important feature of this integration is a
family of XML data formats, called HepML.Comment: 4 pages, 0 figures. To be published in proceedings of CHEP0
Epitaxial Growth of LaSrFeO thin films by laser ablation
We report on the synthesis of high quality LaSrFeO (LSFO)
thin films using the pulsed laser deposition technique on both SrTiO (STO)
and LaAlO (LAO) substrates (100)-oriented. From X-Ray diffraction (XRD)
studies, we find that the films have an out-of-plane lattice parameter around
0.3865nm, almost independent of the substrate (i.e. the nature of the strains).
The transport properties reveal that, while LSFO films deposited on STO exhibit
an anomaly in the resistivity vs temperature at 180K (corresponding to the
charge-ordered transition and associated with a transition from a paramagnetic
to an antiferromagnetic state), the films grown on LAO display a very small
magnetoresistance behavior and present an hysteresis around 270K under the
application of a 4T magnetic field. The changes in transport properties between
both substrates are discussed and compared with the corresponding single
crystals.Comment: 9 pages, 4 figure
A Spherically Symmetric Closed Universe as an Example of a 2D Dilatonic Model
We study the two-dimensional (2D) dilatonic model describing a massless
scalar field minimally coupled to the spherically reduced Einstein-Hilbert
gravity. The general solution of this model is given in the case when a Killing
vector is present. When interpreted in four dimensions, the solution describes
either a static or a homogeneous collision of incoming and outgoing null dust
streams with spherical symmetry. The homogeneous Universe is closed.Comment: 5 pages, 2 figures, to appear in Physical Review
Full capacitance matrix of coupled quantum dot arrays: static and dynamical effects
We numerically calculated the full capacitance matrices for both
one-dimensional (1D) and two-dimensional (2D) quantum-dot arrays. We found it
is necessary to use the full capacitance matrix in modeling coupled quantum dot
arrays due to weaker screening in these systems in comparison with arrays of
normal metal tunnel junctions. The static soliton potential distributions in
both 1D and 2D arrays are well approximated by the unscreened (1/r) coulomb
potential, instead of the exponential fall-off expected from the often used
nearest neighbor approximation. The Coulomb potential approximation also
provides a simple expression for the full inverse capacitance matrix of uniform
quantum dot arrays. In terms of dynamics, we compare the current-voltage (I-V)
characteristics of voltage biased 1D arrays using either the full capacitance
matrix or its nearest neighbor approximation. The I-V curves show clear
differences and the differences become more pronounced when larger arrays are
considered.Comment: 8 pages preprint format, 3 PostScript figure
KtJet: A C++ implementation of the Kt clustering algorithm
A C++ implementation of the Kt jet algorithm for high energy particle collisions is presented. The time performance of this implementation is comparable to the widely used Fortran implementation. Identical algorithmic functionality is provided, with a clean and intuitive user interface and additional recombination schemes. A short description of the algorithm and examples of its use are given
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