Precision Measurements of Vector Boson Scattering Production and Searches for Charged Higgs Bosons at the Large Hadron Collider

<!--HTML-->This thesis presents measurements of cross sections of vector boson pair production in association with two jets and a search for charged Higgs bosons (H$^{±}$) decaying in to a top and a bottom quark.<br>The data samples used for the measurements are LHC proton-proton collisions recorded with the CMS detector during 2016-2018 at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 137 fb$^{-1}$ . The measurements are performed in the fully leptonic decay modes W$^{±}$Z $\to$ $l$$^{±}$ where $l$, $l$' = e, $\mu$, for the WZ and W$^{±}$W$^{±}$ productions; and also in the fully hadronic decay modes VV $\to$ 4q and ZV $\to$ 2v2q, where V = W, Z, for the W$^{±}$W$^{±}$,W$^{+}$W$^{-}$, WZ, and ZZ productions. In the leptonic channel, differential fiducial cross sections as functions of the invariant masses of the jet and charged lepton pairs, as well as of the leading-lepton transverse momentum, are measured for W$^{±}$W$^{±}$ production, and as a function of the invariant mass of the jet pair is also measured for WZ production. All measurements are consistent with the standard model predictions. An observation of electroweak production of WZ boson pairs is reported with an observed (expected) significance of 6.8 (5.3) standard deviations. In the hadronic channel, an expected significance of 3.9 standard deviations is reported for the total electroweak production of VV boson pairs. In both channels, constraints are obtained on the structure of quartic vector boson interactions in the framework of effective field theory.<br>The search for H$^{±}$ is performed in the all-jet final state using LHC proton-proton collision data recorded with the CMS detector in 2016 at $\sqrt{s}$ = 13 TeV, which corresponds to an integrated luminosity of 35.9 fb$^{-1}$ . No significant excess is observed above the expected background. Model-independent upper limits at 95% confidence level are set on the product of the H$^{±}$ production cross section and branching fraction for H$^{±}$ mass hypotheses up to 3 TeV in two production mechanisms. These results are interpreted using different minimal supersymmetric extensions of the standard model, and results combining this with a search in leptonic final states are also reported.