The CMS Phase I Pixel Upgrade and Search for ttbar Resonances in Boosted Semileptonic Final States

The pixel detector is an integral part of the CMS silicon tracker, designed to measure the position and momentum of charged particles produced in high-energy collisions at the Large Hadron Collider (LHC). The phase I upgrade of the CMS forward pixel detector has replaced the previous forward pixel detector in early 2017. In this thesis, I will discuss the testing and qualification procedures for the modules and half cylinders of the CMS Phase I FPIX detector. This thesis also presents a model-independent search for the production of heavy resonances decaying into top-antitop quark pairs using data recorded by the CMS detector in 2018 (integrated luminosity of 58.8 /fb). The analysis focuses on the semi-leptonic decaying channel of the top-antitop quark pair. I focus on events that contain one muon, large missing transverse momentum and at least two high transverse momentum jets, and use special event reconstruction techniques that are optimized for top quarks with high Lorentz boosts.