Event

The ATLAS experiment, consisting of over 3,000 members, explores new frontiers in physics with high-energy proton-proton collisions at the LHC. In such a large collaboration, it is crucial to devote oneself to multiple topics to grasp the big picture of the experiment, from detector operation to physics analysis.

The seminar will focus on two topics from the speaker’s experience in ATLAS. Part 1 highlights the development, commissioning, and operation of the Level-1 muon trigger system for the ongoing LHC Run 3. The Level-1 muon trigger system has been significantly upgraded for Run 3 to process inputs from new inner muon detectors. Stable operation and data-taking have been achieved; particular emphases will be put on the developments of systematic control softwares, monitoring and recovery procedures, and a new software-based readout system. Part 2 highlights the search analysis for supersymmetry with full Run 2 data. MSSM models having higgsinos with compressed mass spectra are viable candidates of physics beyond the Standard Model. Dedicated low-momentum lepton identification and neural network based event selection methods have been developed to ameliorate the sensitivity to higgsinos. As the search analysis is still in progress, tentative results will be presented.