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May 8 – 12, 2023
Norfolk Waterside Marriott
US/Eastern timezone

The AtlFast3, the ATLAS fast simulation tool in Run3

May 8, 2023, 2:30 PM
Chesapeake Meeting Room (Norfolk Waterside Marriott)

Chesapeake Meeting Room

Norfolk Waterside Marriott

235 East Main Street, Norfolk, VA, 23510
Oral Track 3 - Offline Computing Track 3+9 Crossover


Dr Faucci Giannelli, Michele (INFN Roma Tor Vergata)


AtlFast3 is the new, high-precision fast simulation in ATLAS that was deployed by the collaboration to replace AtlFastII, the fast simulation tool that was successfully used for most of Run2. AtlFast3 combines a parametrization-based Fast Calorimeter Simulation and a new machine-learning-based Fast Calorimeter Simulation based on Generative Adversarial Networks (GANs). The new fast simulation can reproduce the Geant4 inputs with higher accuracy than the old AtlFast2. In particular, the simulation of jets of particles reconstructed with large radii and the detailed description of their substructure are significantly improved in AtlFast3. Results will be presented on the performance of the new AtlFast3 that will be deployed for the simulation of the majority of events in Run3; these changes are crucial for achieving the precision needed by analyses that will need to rely mainly on fast simulation.

Consider for long presentation No

Primary authors

Dr Young, Christopher (Albert-Ludwigs-Universitaet Freiburg) Dr Faucci Giannelli, Michele (INFN Roma Tor Vergata) Dr Bandieramonte, Marilena (University of Pittsburgh) Dr Lari, Tommaso (INFN Milano )

Presentation materials