Performance of the ATLAS ID tracking and new LLP triggers in the LHC’s Run 3

The performance of the Inner Detector tracking trigger of the ATLAS experiment at the Large Hadron Collider (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 customized 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 customized 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.