Inclusive Search for a Lorentz-Boosted Higgs Boson Decaying into Bottom QuarksKwok, Ka Hei MartincreatorLandsber, GregAdvisorFan, JijiReaderCutts, DavidReaderBrown University. Department of Physicssponsor2020xxxviii, 231 p.born digitalThesis (Ph. D.)--Brown University, 2020thesesSince the discovery of the Higgs boson in 2012, significant efforts have been put into establishing its coupling to fermions, which is an essential feature of the Higgs boson in the standard model of particle physics. Although the Higgs boson has the largest branching fraction for a decay into bottom quarks, the measurements in this decay mode have to rely on associated production with vector bosons to overcome the overwhelming QCD jet backgrounds. This thesis presents a novel approach that searches for inclusive $\mathrm{H}\to\mathrm{b}\overline{\mathrm{b}}$ decays using jet substructure variables and a b tagging technique based on a deep neural network. This approach explores Higgs boson production at high transverse momentum, which is a complementary phase space region to that in conventional measurements. Results are compared with the latest theoretical predictions at full next-to-leading order accuracy, including finite top quark mass effects. The data sample was collected by the CMS experiment at the LHC at $\sqrt{s}=13~\mathrm{TeV}$, and corresponds to an integrated luminosity of $137~\mathrm{fb}^{-1}$. The method is validated with $\mathrm{Z}\to\mathrm{b}\overline{\mathrm{b}}$ decays. For a Higgs boson mass of $125~\mathrm{GeV}$, an excess of events above the expected background is observed (expected) with a local significance of 2.54 (0,71) standard deviations. The corresponding signal strength is measured to be $\mu_\mathrm{H} = 3.68 \pm 1.20(\mathrm{stat})_{-0.66}^{+0.63}(\mathrm{syst})_{-0.46}^{+0.81}(\mathrm{thy})$ with respect to the standard model predictions. Additionally, an unfolded differential cross section, as a function of the Higgs boson transverse momentum is presented.LHCCMS ExperimentHiggs bosonsbtaggingEnglishRPB20210607dissertations