The coupling of the Higgs boson to other particles is probed by measuring the production cross sections at the Large Hadron Collider using the ATLAS detector. The present measurement is performed using the H->ZZ*->4l decay channel, with l= electron or muon and with datasets corresponding to various integrated luminosities. The inclusive production cross section is measured to be 1.34 +/- 0.12 pb, which is in good agreement with the predicted value of 1.33 +/- 0.08 pb. The gluon-gluon fusion, the vector boson fusion, the vector boson associated and the top associated production cross sections are measured to be 1.12 +/- 0.12 pb, 110 +/- 40 fb, 75 +61 -49 fb and 27 +26 -17 fb, respectively. The differential production cross sections are also measured using the Simplified Template cross sections framework. All measurements are in good agreement with the Standard Model predictions. These results are used to measure the Higgs boson coupling to fermions and vector bosons using the kappa-framework and to derive constraints on contributions from beyond the Standard Model physics using an effective field theory approach. No significant deviations from the Standard Model are observed.

This thesis presents measurements of the Higgs boson inclusive and differential cross sections with 36.1 fb-1 of proton-proton collision data from the Large Hadron Collider at a center of mass energy of 13 TeV recorded with the ATLAS detector. The cross sections are measured in the fiducial phase space of the H ZZ* 4l (four lepton) decay channel as well as in the total Higgs phase space, combining data from the H ZZ* 4l and H [double gamma] (diphoton) decay channels. These two channels have high sensitivity to the Higgs signal and allow for full reconstruction of the Higgs boson kinematics. Unfolding techniques are used to correct for detector effects in the measurements, and comparisons are made to various state-of-the-art Standard Model theory predictions such as the predicted gluon-gluon fusion total cross section at N3LO and the Higgs differential transverse momentum spectrum at NNLO. These precision measurements are used to set limits on anomalous Higgs boson couplings beyond the Standard Model within the framework of pseudo-observables. In the H ZZ * 4l analysis, the inclusive fiducial Higgs boson cross section is measured to be 3.62 [plus/minus] 0.50 (stat) +0.25/-0.20 (sys) fb, in agreement with the Standard Model prediction of 2.91 [plus/minus] 0.13 fb. In the combined analysis, the inclusive total cross section is measured to be 57.0 +6.0/-5.9 (stat.) +4.0/-3.3 (syst.) pb, in agreement with the Standard Model prediction of of 55.6 [plus/minus] 2.5 pb. Measured differential cross sections are also presented for the Higgs transverse momentum, Higgs rapidity, number of associated jets, leading jet transverse momentum, and other kinematic variables.

This Thesis describes the first measurement of, and constraints on, Higgs boson production in the vector boson fusion mode, where the Higgs decays to b quarks (the most common decay channel), at the LHC. The vector boson fusion mode, in which the Higgs is produced simultaneously with a pair of quark jets, provides an unparalleled opportunity to study the detailed properties of the Higgs, including the possibility of parity and CP violation, as well as its couplings and mass. It thus opens up this new field of study for precision investigation as the LHC increases in energy and intensity, leading the way to this new and exciting arena of precision Higgs research.

Precision measurements of the Higgs boson’s properties are a powerful tool to look for deviations from the predictions of the Standard Model (SM) of particle physics. The 139/fb of proton-proton collision data which have been collected by the ATLAS experiment during Run 2 of the LHC, offer an opportunity to investigate rare Higgs-boson topologies, which are particularly sensitive to new physics scenarios but experimentally difficult to access. Several such measurements, which target Higgs-boson decays to heavy-flavour quarks, as well as their combinations are presented in this thesis. A novel analysis that measures Higgs-boson production in association with a heavy vector boson V (VH, with V=W,Z) at high energies is presented. Dedicated Higgs-boson reconstruction techniques are applied to reconstruct the highly Lorentz-boosted Higgs-boson decays into pairs of bottom quarks. The measurement is subsequently combined with a VH cross-section measurement at low and intermediate pT(V) to provide a differential cross-section measurement in kinematic fiducial volumes over the largest possible pT(V) range. All cross-section measurements agree with the SM predictions within relative uncertainties that range from 30% to 300%. The results are furthermore interpreted as limits on the parameters of a SM effective field theory. Finally, a combination of measurements of Higgs decays to heavy-flavour quarks is used to experimentally determine that the Higgs-boson coupling to charm quarks is weaker than to bottom quarks, as predicted by the SM. The target audience for the thesis are physicists and physics students, in particular those with a background in high energy physics.