Speaker
Dr
Cibran Santamarina Rios
(European Organization for Nuclear Research (CERN))
Description
In this presentation we will discuss the design and functioning of a new tool that
runs the ATLAS High Level Trigger Software on Event Summary Data (ESD) files, the
format for data analysis in the experiment. An example of how to implement a sequence
of algorithms based on the electrons selection will be shown.
Summary
The High Level Trigger system of the ATLAS detector has to reduce the LVL1
output rate a factor of one thousand before events are stored in tape. The
reduction is done in two steps: LVL2 and EF. Both trigger levels run
offline-based software algorithms that analyze portions of the event
in a Region of Interest (RoI) given by the previous level. There
exists two kinds of algorithms: Feature extraction (that reconstruct
objects in the RoI) and Hypothesis algorithms (that perform the
selection criteria based on the objects reconstructed before). The
execution of the algorithms sequence is guided by the HLT steering
package, one of the back-bones of the HLT software architecture.
In this presentation we will describe how to implement a sequence of
algorithms based on the electrons selection example and discuss the design
and functioning of a new tool that runs the HLT Steering on ATLAS Event
Summary Data (ESD) files, the data format that will be used for data
analysis. This tool consists of a full prototype of a Trigger chain that,
substituting the standard trigger Feature Extraction Algorithms by
unpacking algorithms gathering data from ESDs, permits the testing of the
full ATLAS trigger menu in a fast mode. The tool will be used for Trigger
debugging and efficiency calculation when the data taking starts. An
example based on optimization for high transverse momentum electrons
selection will be shown.
Author
Dr
Cibran Santamarina Rios
(European Organization for Nuclear Research (CERN))
