Background Modelling in the ATLAS H to yy Differential Cross Section Analysis

Differential cross section measurements are an important part of the efforts to precisely measure the Higgs boson properties, providing model-independent measurements of kinematic and event observables. This poster presents the H to yy differential cross section analysis using the full Run-2 data set taken between 2015 and 2018 at the ATLAS experiment. The analysis uses analytical functions to extract the signal yield in its signal + background fit to data, subsequently unfolding the fitted yields to the particle level. The background fit function is chosen from a list of considered functional forms by evaluating the potential measurement bias for each function using MC simulated samples. An emphasis is put on the explanation of the background modelling strategy and the estimation of the potential bias introduced to the measurement by the background model choice

Background Modelling in the ATLAS H→γγH \rightarrow \gamma \gamma Differential Cross Section Analysis

Measurements of fiducial integrated and differential cross sections of the Higgs boson decaying into a pair of photons are presented with an emphasis on discussing the background modelling strategy. The measurements use the full ATLAS dataset corresponding to 139 fb$^{−1}$ of proton-proton collision data recorded during the 2015 - 2018 Run-2 of the Large Hadron Collider. Several diphoton and jet distributions related to the event kinematics as well as the multiplicity of the jets produced in association with the Higgs boson are measured and show good agreement with the Standard Model prediction. All presented results are unfolded to particle level. The integrated fiducial production cross section is measured to be 65.2±7.1 fb, which is in good agreement with the Standard Model prediction of 63.6±3.3fb