W$^+$W$^-$ BOSON PAIR PRODUCTION IN PROTON-PROTON COLLISIONS AT CENTER-OF-MASS ENERGY OF $\sqrt{s}=13~\mathrm{TeV}$ WITH THE CMS DETECTOR AT THE LHC

A measurement of the W$^+$W$^-$ boson pair production cross section in proton-proton collisions at a center-of-mass energy of 13 TeV is presented. The data used in this study are collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The W$^+$W$^-$ candidate events are selected by requiring two oppositely charged leptons. The total W$^+$W$^-$ production cross section measurement has been $117.6 \pm 6.8$ pb, which agrees well with the theoretical prediction. Fiducial cross sections and differential cross sections are also reported, which also agree well with the theoretical prediction. Finally, constraints on the dimension-6 operators in the context of an effective field theory are derived. This analysis provides some of the strongest constraints compared with previous results. \\ A search for dark matter in proton-proton collisions at a center-of-mass energy of 13 TeV is performed using events with a W$^+$W$^-$ boson pair and large missing transverse momentum. The data used in this study are collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb$^{-1}$. The W$^+$W$^-$ candidate events are selected by requiring two oppositely charged leptons. No significant excess over the expected standard model prediction is observed. Limits are set on dark matter production in the context of the dark Higgs simplified model, with a dark Higgs mass above the W$^+$W$^-$ pair mass threshold. The results presented correspond to the first measurement carried out in the CMS experiment using this novel interpretation. \\ Deep learning techniques are applied to estimate the transverse momentum of highly energetic muons in the CMS detector. The main goal of these studies is to improve the results of the current procedure, and if so, consider including these types of methodologies in the future data taking of the experiment. The preliminary results obtained, based on simulation, show an improvement of about 25$\%$ in the resolution of the transverse momentum for muons with 1500 $ \leq p_ {T} \leq $ 2500 GeV and $ \lvert \eta \rvert <$ 0.9.