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Grid interoperability: joining grid information systems
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, High Energy Physics. (ATLAS)
2007 (English)In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 119, no 6, 062030- p.Article in journal (Refereed) Published
Abstract [en]

A grid is defined as being 'coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organizations'. Over recent years a number of grid projects, many of which have a strong regional presence, have emerged to help coordinate institutions and enable grids. Today, we face a situation where a number of grid projects exist, most of which are using slightly different middleware. Grid interoperation is trying to bridge these differences and enable Virtual Organizations to access resources at the institutions independent of their grid project affiliation. Grid interoperation is usually a bilateral activity between two grid infrastructures. Recently within the Open Grid Forum, the Grid Interoperability Now (GIN) Community Group is trying to build upon these bilateral activities. The GIN group is a focal point where all the infrastructures can come together to share ideas and experiences on grid interoperation. It is hoped that each bilateral activity will bring us one step closer to the overall goal of a uniform grid landscape. A fundamental aspect of a grid is the information system, which is used to find available grid services. As different grids use different information systems, interoperation between these systems is crucial for grid interoperability. This paper describes the work carried out to overcome these differences between a number of grid projects and the experiences gained. It focuses on the different techniques used and highlights the important areas for future standardization.

Place, publisher, year, edition, pages
2007. Vol. 119, no 6, 062030- p.
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-110772DOI: 10.1088/1742-6596/119/6/062030OAI: oai:DiVA.org:uu-110772DiVA: diva2:278224
Proceedings of CHEP07Available from: 2009-11-24 Created: 2009-11-24 Last updated: 2011-04-21Bibliographically approved
In thesis
1. Looking for the Charged Higgs Boson: Simulation Studies for the ATLAS Experiment
Open this publication in new window or tab >>Looking for the Charged Higgs Boson: Simulation Studies for the ATLAS Experiment
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The discovery of a charged Higgs boson (H+) would be an unambiguous sign of physics beyond the Standard Model. This thesis describes preparations for the H+ search with the ATLAS experiment at the Large Hadron Collider at CERN. The H+ discovery potential is evaluated, and tools for H+ searches are developed and refined.

The H+→τν decay mode has been known as the most promising H+ discovery channel. Within this thesis, first studies of this channel with realistic detector simulation, trigger simulation and consideration of all dominant systematic uncertainties have been performed. Although, as shown by these studies, the discovery sensitivity is significantly degraded compared to studies using a parametrized detector simulation, this channel remains the most powerful ATLAS H+ discovery mode. Future searches will rely on multivariate analysis techniques like the Iterative Discriminant Analysis (IDA) method. First studies indicate that a significant sensitivity increase can be achieved compared to studies based on sequential cuts. The largest uncertainty in H+ searches is the expected $t\bar{t}$ background contribution. It is shown that numbers obtained from simulated events could be off by a factor of two, decreasing the discovery sensitivity dramatically. In this thesis, the Embedding Method for data-driven background estimation is presented. By replacing the muon signature in $t\bar{t}$ events with a simulated τ, events which allow an estimation of the background contribution at the 10% level are obtained.

The ATLAS τ identification focuses on comparably clean environments like Z and W decays. To optimize the performance in high-multiplicity events like H+→τν, tau leptons are studied in $t\bar{t}$ and pile-up events. Variables which do not show discrimination power in high-multiplicity events are identified, and in some cases similar, more powerful variables are found. This allows to recover some of the performance loss and to increase the robustness of the τ identification.

For the analysis of large amounts of data produced by the ATLAS detector, seamless interoperability of the various Grid flavors is required. This thesis introduces translators to overcome differences in the information system between a number of Grid projects,and highlights important areas for future standardization.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2010. VI+50 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 696
charged Higgs, tau, ATLAS, HEP, CERN, LHC, Particle Physics, Grid
National Category
Physical Sciences
Research subject
High Energy Physics
urn:nbn:se:uu:diva-110882 (URN)978-91-554-7676-2 (ISBN)
Public defence
2010-01-15, Polhemsalen, Ångström Laboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Available from: 2009-12-22 Created: 2009-11-30 Last updated: 2009-12-22Bibliographically approved

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