CERN Accelerating science

ATLAS Slides
Report number ATL-DAQ-SLIDE-2025-420
Title GELATO: A Generic Event-Level Anomalous Trigger Option for ATLAS in LHC Run 3
Author(s) Sugizaki, Kaito (University of Pennsylvania (US)) ; ATLAS Collaboration
Corporate author(s) The ATLAS collaboration
Collaboration ATLAS Collaboration
Submitted to The 32nd International Symposium on Lepton Photon Interactions at High Energies (Lepton Photon 2025), Madison, Wisconsin, Us, 25 - 29 Aug 2025
Submitted by kaito.sugizaki@cern.ch on 01 Sep 2025
Subject category Particle Physics - Experiment
Accelerator/Facility, Experiment CERN LHC ; ATLAS
Free keywords Trigger ; TDAQ ; Anomaly Detection ; Level-1 ; HLT ; Run 3
Abstract Search for physics beyond the Standard Model has been a long-standing subject at the LHC. The absence of such signatures indicates that new physics may elude standard triggers; conventional triggers at the ATLAS experiment are constructed by setting thresholds on variables such as the particle momentum, targeting event topologies exclusive to specific models. Anomaly detection, a form of unsupervised machine learning, enables searches for signatures which deviate from the Standard Model without relying on particular model assumptions. We present the first anomaly detection trigger at ATLAS, newly developed and integrated for data-taking in LHC Run 3. In addition to its design and expected performance, we discuss its commissioning, validation, and operational robustness, along with some look in the newly collected data. The first anomaly detection trigger in ATLAS marks a milestone for machine learning-based, next-generation triggers and model-agnostic searches for new physics.



 Record created 2025-09-01, last modified 2025-09-02