Measurement of the decay of the Higgs boson to charm quarks provides a direct probe of the Higgs coupling to second-generation quarks. Therefore, it is crucial for understanding the structure of Yukawa couplings. In this thesis, a search for the Higgs boson decaying to charm quarks with the CMS experiment is presented. The search is designed for Lorentz-boosted Higgs bosons produced in association with vector (V) bosons (W or Z bosons). A novel approach that reconstructs both quarks from the Higgs boson decay with a single large-radius jet is adopted. The charm quark pair is identified with an advanced deep learning--based algorithm. This approach leads to a highly competitive result: Using proton-proton collision data corresponding to an integrated luminosity of 35.9 fb-1, an observed (expected) upper limit on the VH cross section times the H->cc branching fraction of 71 (49) times the standard model expectation at 95% confidence level is obtained.

A detailed description of the deep learning--based boosted object identification algorithm is also presented in this thesis. It is a versatile algorithm designed to identify and classify hadronic decays of highly Lorentz-boosted top quarks and W, Z, Higgs bosons. Using deep neural networks to directly access and process the raw information of all constituent particle-flow candidates of a jet, this advanced algorithm has achieved significant performance improvements compared to traditional approaches.

As successful as the Standard Model of particle physics has been it still has several major shortcomings which range from unanswered theoretical questions to a lack of any explanation for observed phenomena such as dark matter. One proposed theory for physics beyond the Standard Model which provides solutions for some of these issues is supersymmetry. This dissertation presents a search for supersymmetry using 2.3 fb^(-1) of proton-proton collision data. This data was collected at a center-of-mass energy of 13 TeV by the CMS detector at the LHC during 2015. This search focuses on top squark pair production where the produced stops both decay to an all hadronic final state. These decays are characterized by multiple jets and missing transverse momentum. A baseline search region is defined to be sensitive to signal processes which occur at rates many orders of magnitude lower than Standard Model processes. The sensitivity to various signal models is improved by dividing this baseline region into distinct categories. Events with an unreconstructed lepton from leptonic W boson decays constitute the primary background. There are also significant contributions from events where a Z boson decays invisibly to neutrinos especially in bins with higher missing transverse momentum. Events with multijet production where one jet has been severely mis-measured as well as those with a pair of top quarks and an invisibly decaying Z boson also have a small presence in the search region. The contributions from these processes to the search region is estimated using data control regions. No statistically significant deviations from the predicted background yields are observed. The results are interpreted in terms of exclusion limits using the Simplified Model Spectrum framework. Stop and neutralino masses are probed up to 780 GeV and 260 GeV respectively.