RECHERCHE DE QUARK TOP DEPLACE DANS LE TRAJECTOGRAPHE DE L'EXPERIENCE CMS AU LHC

This thesis presents two instrumental and analysis studies both based on proton-proton collisions data from the CMS experiment during Run 2 and Run 3 at the LHC with a center-of-mass energy of $\sqrt{s}=13$ TeV and $\sqrt{s}=13.6$ TeV. The first study is devoted to the monitoring of the ageing of the silicon strip tracker of CMS. The second topic is a search for new physics with the CMS tracker.\newline

The tracker of CMS is exposed to high level of radiation damaging the lattice of the silicon sensors. Dedicated monitoring of the silicon strip sensors via the full depletion voltage is needed to ensure good data-taking with an extrapolation towards the end of Run 3 and beyond. An new method t oestimate the full depletion voltage is proposed. \newline

The second study is a search for displaced top quark within the tracker volume of the CMS experiment at the LHC.  The search relies on the reconstruction of displaced vertices to identify the signal events and estimate the background in the signal region. The analysis is being under review by the CMS collaboration, thus still blinded to the signal region but expected limits are provided.