Tracker performance studies at the 100 TeV future circular hadron collider at extreme pile-up conditions

In high energy physics collider experiments the finding and measurement of trajectories of charged particles in the innermost tracking detector is one of the most challenging aspects of event reconstruction. It is particularly strongly influenced by the presence of pile-up and becomes computationally challenging in such environments. The ATLAS experiment, at the LHC (Large Hadron Collider) is planing a large-scale upgrade ($Phase-II upgrade$) to handle the experimental conditions of the next run $Run4$, which includes a new inner tracking detector. To cope with the environment of up to 200 simultaneous proton-proton collision per bunch-crossing ($pile-up$) both, hardware and software components need to be significantly updated. At the same time, post LHC circular collider possibilities are examined in the frame of the FCC (future circular collider) design study. For a future proton-proton collider ($FCC-hh$) with a center-of-mass-energy of 100 TeV 1000 pile-up interactions are expected. The main challenges for a FCC-hh scenario in terms track reconstruction are expected to be the resolution of close-by tracks in dense jet environments and dealing with the extreme pile-up conditions. Moreover, the complex experimental setup leads to demanding computational aspects in track reconstruction and simulation. At the beginning of the study, a FCC software suite was established, which should profit from the LHC legacy and ongoing research and development for the upcoming detector upgrades.\ This work is embedded in the future circular collider study. The first part of this work describes the development of software components for simulation and modern track reconstruction for future scenarios. The usage of modern programming techniques, respecting the evolution of the computing hardware by exploiting parallel computing approaches, while aiming on optimizing the physics potential, in particular for high pile-up environments, was essential. The software suite was substantially extended to allow tracker performance studies. The optimized and newly developed software was used to study the tracker performance and physics potential of the FCC-hh baseline tracker, considering the extreme pile-up conditions. These aspects have been studied by examining the expected channel occupancy and data rates as well as double track resolution in the core of b-quark particle jets. Finally the potential of directly detecting a possible WIMP (Weakly Interacting Massive Particle) dark matter candidate, with disappearing track signature, was assessed.