Conditions and configuration metadata for the ATLAS experiment
Journal of Physics: Conference Series 396:PART 5 (2012)
Abstract:
In the ATLAS experiment, a system called COMA (Conditions/Configuration Metadata for ATLAS), has been developed to make globally important run-level metadata more readily accessible. It is based on a relational database storing directly extracted, refined, reduced, and derived information from system-specific database sources as well as information from non-database sources. This information facilitates a variety of unique dynamic interfaces and provides information to enhance the functionality of other systems. This presentation will give an overview of the components of the COMA system, enumerate its diverse data sources, and give examples of some of the interfaces it facilitates. We list important principles behind COMA schema and interface design, and how features of these principles create coherence and eliminate redundancy among the components of the overall system. In addition, we elucidate how interface logging data has been used to refine COMA content and improve the value and performance of end-user reports and browsers..Evolution of grid-wide access to database resident information in ATLAS using Frontier
Journal of Physics: Conference Series 396:PART 5 (2012)
Abstract:
The ATLAS experiment deployed Frontier technology worldwide during the initial year of LHC collision data taking to enable user analysis jobs running on the Worldwide LHC Computing Grid to access database resident data. Since that time, the deployment model has evolved to optimize resources, improve performance, and streamline maintenance of Frontier and related infrastructure. In this presentation we focus on the specific changes in the deployment and improvements undertaken, such as the optimization of cache and launchpad location, the use of RPMs for more uniform deployment of underlying Frontier related components, improvements in monitoring, optimization of fail-over, and an increasing use of a centrally managed database containing site specific information (for configuration of services and monitoring). In addition, analysis of Frontier logs has allowed us a deeper understanding of problematic queries and understanding of use cases. Use of the system has grown beyond user analysis and subsystem specific tasks such as calibration and alignment, extending into production processing areas, such as initial reconstruction and trigger reprocessing. With a more robust and tuned system, we are better equipped to satisfy the still growing number of diverse clients and the demands of increasingly sophisticated processing and analysis..Exclusive electroproduction of two pions at HERA
European Physical Journal C 72:1 (2012) 1-12
Abstract:
The exclusive electroproduction of two pions in the mass range 0.4Exclusive γγ →+μμ- production in proton-proton collisions at √s = 7 TeV
Journal of High Energy Physics 2012:1 (2012)
Abstract:
A measurement of the exclusive two-photon production of muon pairs in proton-proton collisions at √s = 7TeV, pp → pμ+μ -p, is reported using data corresponding to an integrated luminosity of 40 pb-1. For muon pairs with invariant mass greater than 11:5 GeV, transverse momentum p (μ) > 4 GeV and pseudorapidity σ(μ) < 2:1, a t to the dimuon pT(μ+μ-) distribution results in a measured cross section of η(p → pμ+μ -p) = 3:38+0:580:55 (stat:)±0:16 (syst:)±0:14 (lumi:) pb, consistent with the theoretical prediction evaluated with the event generator Lpair. The ratio to the predicted cross section is 0:83+0:14 -0:13 (stat:) ± 0:04 (syst:) ± 0:03 (lumi:). The characteristic distributions of the muon pairs produced via fusion, such as the muon acoplanarity, the muon pair invariant mass and transverse momentum agree with those from the theory. Copyright © CERN.Forward energy flow, central charged-particle multiplicities, and pseudorapidity gaps in W and Z boson events from pp collisions at √s = 7 TeV
European Physical Journal C 72:1 (2012) 1-28