Speaker
Description
The performance of the Inner Detector tracking trigger of the ATLAS experiment at
the Large Hadron Colloder (LHC) is evaluated for the data taken for LHC Run-3 during 2022.
Included are results from the evolved standard trigger track reconstruction, and from new
unconventional tracking strategies used in the trigger for the first time in Run-3.
From Run-3, the application of Inner Detector tracking in the trigger has been significantly
expanded, in particular full-detector tracking is utilized for hadronic signatures
(such as jets and missing transverse energy triggers) for the first time. To meet computing
resource limitations, several new features, including machine-learning based track seeding,
have been developed and are discussed, together with many additional improvements with respect
to the trigger tracking used in LHC Run-2. The Large Hadron LHC, as the world’s highest energy
particle accelerator, provides a unique opportunity for directly searching for new physics
Beyond the Standard Model (BSM). Massive long-lived particles (LLPs), which are absent in the
Standard Model, can occur in many well-motivated theories of physics BSM. These new massive
LLPs can decay into other particles far from the LHC interaction region, resulting in unusual
experimental signatures and hence requiring customised and complex experimental techniques for
their identification. Prior to Run-3, the ATLAS trigger did not include dedicated tracking
triggers for the explicit identification of massive LLPs decaying in the inner tracking
detectors. To enhance the sensitivity of searches, a series of new triggers customised for
various unconventional tracking signatures, such as "displaced" tracks, and short tracks which
"disappear" within the tracking detector, have been developed for Run-3 data taking, starting
from 2022. The high performance of the inner detector trigger remains essential for the ATLAS
physics programs in the Run-3 data, in particular for the many precision measurements of the
Standard Model and now, in the searches for new physics. For the first time, the development
and performance of these new triggers for the 2022 data taking is presented, together with the
that from standard tracking.
