Mar 21 – 27, 2009
Europe/Prague timezone

Event Selection Services in ATLAS

Mar 23, 2009, 4:30 PM
Club A (Prague)

Club A


Prague Congress Centre 5. května 65, 140 00 Prague 4, Czech Republic
oral Software Components, Tools and Databases Software Components, Tools and Databases


Dr Jack Cranshaw (Argonne National Laboratory)Dr Qizhi Zhang (Argonne National Laboratory)


ATLAS has developed and deployed event-level selection services based upon event metadata records ("tags") and supporting file and database technology. These services allow physicists to extract events that satisfy their selection predicates from any stage of data processing and use them as input to later analyses. One component of these services is a web-based Event-Level Selection Service Interface (ELSSI). ELSSI supports event selection by integrating run-level metadata, luminosity-block-level metadata (e.g., detector status and quality information), and event-by-event information (e.g., triggers passed and physics content). The list of events that pass the physicist's cuts is returned in a form that can be used directly as input to local or distributed analysis; indeed, it is possible to submit a skimming job directly from the ELSSI interface using grid proxy credential delegation. Beyond this, ELSSI allows physicists who may or may not be interested in event-level selections to explore ATLAS event metadata as a means to understand, qualitatively and quantitatively, the distributional characteristics of ATLAS data: to see the highest missing ET events or the events with the most leptons, to count how many events passed a given set of triggers, or to find events that failed a given trigger but nonetheless look relevant to an analysis based upon the results of offline reconstruction, and more. This talk provides an overview of ATLAS event-level selection services, with an emphasis upon the interactive Event-Level Selection Service Interface.

Primary authors

Dr David Malon (Argonne National Laboratory) Dr Elizabeth Gallas (University of Oxford) Florbela Viegas (CERN) Ms Helen McGlone (University of Glasgow) Dr Jack Cranshaw (Argonne National Laboratory) Dr Julius Hrivnac (LAL, Orsay) Dr Marco Mambelli (University of Chicago) Dr Michael Kenyon (University of Glasgow) Dr Qizhi Zhang (Argonne National Laboratory)

Presentation materials