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May 8 – 12, 2023
Norfolk Waterside Marriott
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Faster simulated track reconstruction in the ATLAS Fast Chain

May 8, 2023, 12:15 PM
Hampton Roads Ballroom VI (Norfolk Waterside Marriott)

Hampton Roads Ballroom VI

Norfolk Waterside Marriott

235 East Main Street Norfolk, VA 23510
Oral Track 3 - Offline Computing Track 3 - Offline Computing


Dr Leight, William (University of Massachusetts, Amherst)


The production of simulated datasets for use by physics analyses consumes a large fraction of ATLAS computing resources, a problem that will only get worse as increases in the instantaneous luminosity provided by the LHC lead to more collisions per bunch crossing (pile-up). One of the more resource-intensive steps in the Monte Carlo production is reconstructing the tracks in the ATLAS Inner Detector (ID), which takes up about 60% of the total detector reconstruction time [1]. This talk discusses a novel technique called track overlay, which substantially speeds up the ID reconstruction. In track overlay the pile-up ID tracks are reconstructed ahead of time and overlaid onto the ID tracks from the simulated hard-scatter event. We present our implementation of this track overlay approach as part of the ATLAS Fast Chain simulation, as well as a method for deciding in which cases it is possible to use track overlay in the reconstruction of simulated data without performance degradation.

[1] ATL-PHYS-PUB-2021-012 (60% refers to Run3, mu=50, including large-radius tracking, p11)

Consider for long presentation No

Primary authors

Dr Leight, William (University of Massachusetts, Amherst) Dr Javurkova, Martina (University of Massachusetts, Amherst) Tsai, Fang-Ying (Stony Brook University) Mr Sengupta, Debajyoti (Universite de Geneve) Dr Golling, Tobias (Universite de Geneve)

Presentation materials

Peer reviewing