Speaker
Stewart Martin-Haugh
(STFC - Rutherford Appleton Lab. (GB))
Description
A description of the design and performance of the newly reimplemented
tracking algorithms for the ATLAS trigger for LHC Run 2, to commence in
spring 2015, is provided. The ATLAS High Level Trigger (HLT) has been
restructured to run as a more flexible single stage process, rather than
the two separate Level 2 and Event Filter stages used during Run 1. To
make optimal use of this new scenario, a new tracking strategy has been
implemented for Run 2 for the HLT. This new strategy will use a Fast
Track Finder (FTF) algorithm to directly seed the subsequent Precision
Tracking, and will result in improved track parameter resolution and
significantly faster execution times than achieved during Run 1 but
with no significant reduction in efficiency. The performance and timing
of the algorithms for numerous physics signatures in the trigger are
presented. The profiling infrastructure, constructed to provide prompt
feedback from the optimisation, is described, including the methods used
to monitor the relative perfor- mance improvements as the code evolves.
The online deployment and commissioning, together with the first
measurements with the Run 2 data are also discussed.
Primary author
Stewart Martin-Haugh
(STFC - Rutherford Appleton Lab. (GB))
