Measurement of the Higgs boson properties with Run 2 data collected by the ATLAS experiment

All current measurements of the Higgs boson properties agree very well with the Standard Model predictions. However, theories beyond the Standard Model are needed to explain fundamental open questions. Many of these theories predict deviations in the Higgs sector, in particular in the couplings of the Higgs boson to the elementary particles. These can be tested at the LHC by measuring production and decay rates of the Higgs boson with increasing precision. The measurements are performed in the Simplified Template Cross Section framework, that divides the phase space into production modes and kinematic regions, in order to use shape information in an, as much as possible, model independent approach. This still allows a combination of different decay channels in order to profit from their sensitivities in different phase space regions. The work presented in this documents uses proton-proton collision data recorded at a center-of-mass energy of $\sqrt{s} = 13 TeV$ by the ATLAS detector. Despite a low statistics, the Higgs decay into two photons profits from a very clean experimental signature, an excellent mass resolution and a smooth background. It is therefore an excellent channel to make precision measurements, in particular in phase space regions with high statistics but large background contributions. This thesis presents the Higgs boson mass measurement using 36 fb$^{-1}$ of integrated luminosity, as well as a measurement of its production cross sections using 80 fb$^{-1}$ of data. A crucial ingredient for these measurements is a careful calibration of the photon energy. A complicated calibration chain is applied, correcting for all the possible sources of miscalibration in the detector and the reconstruction. The final step uses the decay of the $Z$ boson into an electron-positron pair as a standard candle. Detailed studies on this step are as well presented in this thesis. Since no concrete hint to a specific new physics model has been found so far, it is important to interprete these measurements in a model independent way. In this work, the combined results in several Higgs decay channels are interpreted in the framework of Effective Field Theories. These results allow to set limits on a complete set of generic operators. The obtained constraints can subsequently be re-interpreted in concrete new physics models.