From detectors to data: Thermal Characterization of CMS Outer Tracker modules and Measurement of the top quark mass using tt+ jet events

This thesis addresses key challenges in modern particle physics by contributing to threecritical areas: the development of particle detectors, their calibration and the analysis ofdata collected in particle physics experiments. Contributions to these areas are presentedin the context of the Compact Muon Solenoid (CMS) experiment at the Large HadronCollider (LHC).The first part of this work focuses on the development and characterization of a temperaturetest system (Burn-in) for silicon modules, essential components of the CMS OuterTracker Upgrade, a central part of the preparation of CMS for the forthcoming High LuminosityLHC running. The Burn-in test involves subjecting the modules to thermal cyclingto identify early failures and ensure long-term reliability. This system demonstrated areliable performance for quality assurance and has been used to conduct thermal characterizationmeasurements of Pixel-Strip modules. In addition, thermal measurementsincluding dees and cooling structures have been performed.In the second part of this thesis, the contribution to the CMS tracker alignment in theongoing LHC run at a center of mass energy ps=13.6 TeV is presented. Alignment is acritical calibration process that ensures the high precision geometry required for accurateparticle tracking. Special attention is given to the interplay between alignment and localpixel reconstruction.The final part of the thesis presents a measurement of the top quark pole mass, usingevents where the top quark-antiquark pairs are produced in association with an energeticjet (t¯t+jet). The proton-proton collision data at ps = 13TeV are used, collected by theCMS and corresponding to the integrated luminosity of 138 fb