A lepton pair and jets final state in CMS and unitarity interpretations

This thesis addresses the study of a signature with a pair of same flavor leptons and jets with the CMS detector in the context of two different scenarios: precision physics within the Standard Model, and the effective theory of composite models. On one hand, the dilepton plus jets signature allows the selection of the Vector Boson Scattering process of a ZV in the semi-leptonic final state, where V is the vector boson decaying hadronically (V=W, Z) and Z decays in charged leptons ($e$,$\mu$), in proton-proton collisions at 13 TeV. In addition, the dilepton plus jets final state can also be exploited in LHC and in future collider (HL/HE-LHC) data to search for the presence of new exotic states (Majorana neutrinos) arising from a compositeness framework. Constraints from unitarity are considered for the first time and are shown to play a fundamental role in the sensitivity of new physics searches.