Abstract: The ATLAS Detector, below the surface of the Swiss-French border, measures the remnants of high-energy proton-proton collisions, accelerated by the Large Hadron Collider (LHC) at CERN. A little over a year ago the LHC paused operations, having delivered an integrated luminosity corresponding to 150 fb^−1 of data at a centre-of-mass energy of 13 TeV. This talk will describe a search for physics beyond the Standard Model using that dataset, as well as the charged particle tracking detector technology that renders it possible.

Searching for rare processes requires sifting through a large amount of data, so in 2027 the LHC will enter a High Luminosity phase (HL-LHC), increasing the instantaneous luminosity by a factor of five and delivering 4000 fb^-1 within twelve years. This will impose significant technical challenges on all aspects of the ATLAS detector, resulting in the entire Inner Detector being replaced by an all-silicon tracker. ITk (the new “Inner TracKer”) will be comprised of Strip and Pixel detectors. This talk will also discuss the design of the ITk Pixel detector to handle the increased number of hits per chip and modeling of the damage to the silicon sensor, both to predict the detector performance and to understand the effects of radiation damage on data taking.