Looking for new physics: Search for anomalous gauge couplings in WW and WZ production in lepton + jet events in proton-proton collisions at 13 TeV with the CMS experiment

The LHC Run 2, with a centre-of-mass energy of 13 TeV, has opened new avenues for searching possible effects of physics beyond the standard model. Such new physics can be parametrised by adding additional operators to the standard model Lagrangian in a model-independent effective field theory approach. In this thesis, a search is presented for three operators that would lead to anomalous WWgamma or WWZ couplings. They are constrained by studying proton-proton collision events, recorded by the CMS experiment, in which two vector bosons are produced; a W boson which decays into a charged lepton and the corresponding neutrino, and a W or Z boson which decays into hadrons that are reconstructed as a single, large-radius jet. Using reconstructed kinematic variable distributions, one- and two-dimensional 95% confidence intervals are obtained for the anomalous coupling parameters. The obtained limits, $-1.58 < c_\rm{WWW}/\Lambda^2 < 1.59~\TeV^{-2}$, $-2.00 < c_\rm{W}/\Lambda^2 < 2.65~ \TeV^{-2}$, and $-8.78 < c_\rm{B}/\Lambda^2 < 8.54~\TeV^{-2}$, are the strictest bounds on these parameters to date.