Abstract:
The search for phenomena beyond the Standard Model (SM) is one of the primary objectives of the experiments recording proton-proton collisions at the CERN Large Hadron Collider (LHC), presenting significant challenges to researchers. At the Compact Muon Solenoid (CMS) experiment, two complementary approaches are employed: direct searches for previously unobserved particles and the identification of deviations in well-understood SM processes. In this context, third-generation fermions and weak bosons play a key role in extending insights into new physics. In this seminar, an example of a direct search for new physics will be provided through a brief overview of a hypothetical massive W' boson. Following this, the focus will shift to the Effective Field Theory (EFT) framework, which models potential deviations from SM expectations. Special attention will be given to its implementation in vector boson scattering (VBS) and the top quark sector, with a focus on final states involving at least two charged leptons. The insights provided by EFT investigations are essential to complement direct BSM searches, offering a comprehensive picture of how current and future collider experiments can probe the limits of the Standard Model and explore new physics.