During Run 1 of LHC, the ATLAS and CMS collaboration firmly established the existence of a Higgs boson. The larger Run 2 dataset allows us to probe the Higgs sector in greater detail. Within the H->ZZ->4l channel, we have measured the various properties of the new resonance, providing the crucial input for Standard Model predictions. In this talk, I will present the measurement of the Higgs boson mass with a focus on the various required ingredients, such as muon momentum calibration & ML algorithms to reduce backgrounds and account for per-event resolution.
ATLAS has an extensive detector upgrade plan to allow itself to collect and exploit the data delivered during HL-LHC. The upgrade of the current trigger system is one of those project. I will focus on the EF Tracking sub-system, that will allow track reconstruction at trigger level at the HL-LHC. I will present the various ML-based accelerator-optimized algorithms that enable this reconstruction in a fast and an efficient manner and open previously unexplored phase space for new physics.
