M.A.R.S.: The momentum spectrum of muons to 800 GeVc in the vertical direction

The sea-level vertical muon differential momentum spectrum has been measured using the Durham spectrograph MARS in the region 20 GeV/c to 500 GeV/c. The instrumental biases have been studied in detail and allowances made for the particle detector inefficiencies to render to measurement absolute. A simple muon production and propagation model has been used to predict the pion and kaon production spectra from the muon spectrum measurements. It has been found impossible to fit, with any degree of significance, a constant exponent power law pion and kaon production spectrum, having a reasonable value of the K/π ratio (0.15). A better fit is obtained if the exponent is allowed to increase with momentum, and in particular a model with two values of the exponent has been fitted. The muon spectrum has been extrapolated both above and below 500 GeV/c and 20 CeV/c respectively, and at low momenta good agreement is found with the recent "form fit" of De et al. (1972). The present results are compared with previous and contempary measurements of the muon spectrum with the conclusion that there is no evidence, from other recent measurements, that they are incorrect. Comparison with surveys of indirect measurements at higher energies however suggest that the muon spectrum cannot continue in this enhanced fashion much beyond 1000 GeV. Finally an absolute integral rate experiment has been performed using MARS as a range spectrograph, and the intensity above 7.12 GeV/c is found to be in agreement with a previous similar measurement made with the instrument. Further it is concluded that the intensity at this momentum is in agreement with the extrapolation of the differential spectrum measurements below 20 GeV/c

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

LHAPDF : PDF Use from the Tevatron to the LHC

Parton Density Functions (PDFs) and their uncertainties are extremely important topics for both the Tevatron and the LHC. Experiments at the Tevatron can enhance this knowledge not only by constraining the PDF fits, but also by developing and refining the available PDF tools through feed-back from the experiments that are currently analyzing the highest energy hadron collider data available. It is important that the community has standardized tools and methods at its disposal. In this note we summarize briefly the most recent developments of the The Les Houches Accord PDF (LHAPDF), which is the modern replacement for PDFLIB. We also outline and compare the methods of quantifying the impact of PDF uncertainties on physical observables. The PDF weighting method for propagating errors from PDFs to event generator observables is outlined in detail, and example code for using this method with PYTHIA is also included

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

Relationships between reading, tracing and writing skills in introductory programming

This study analyzed student responses to an examination, after the students had completed one semester of instruction in programming. The performance of students on code tracing tasks correlated with their performance on code writing tasks. A correlation was also found between performance on "explain in plain English" tasks and code writing. A stepwise regression, with performance on code writing as the dependent variable, was used to construct a path diagram. The diagram suggests the possibility of a hierarchy of programming related tasks. Knowledge of programming constructs forms the bottom of the hierarchy, with "explain in English", Parson's puzzles, and the tracing of iterative code forming one or more intermediate levels in the hierarchy. Copyright 2008 ACM

Childhood intelligence and personality traits neuroticism and openness contributes to social mobility : A study in the Aberdeen 1936 Birth Cohort

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