Projections for measurements of Higgs boson cross sections, branching ratios, coupling parameters and mass with the ATLAS detector at the HL-LHC

A study is presented on the ATLAS experimental prospects for measuring Higgs boson cross sections, signal strengths and branching ratios, and determining couplings to individual fermions and bosons, at the High Luminosity LHC (HL-LHC) with 3000 fb$^{−1}$ collected at 14 TeV. The results shown here are extrapolated from the Run 2 results using datasets of 36 fb$^{−1}$ and 80 fb$^{−1}$ collected at 13 TeV. The different analyses are combined to compute the expected precision of the measurement of the cross-sections for the main production processes of the Higgs boson and of the branching ratios into its main decay modes as well as their interpretation in terms of modifiers to Higgs boson couplings. It is assumed that the upgraded detector produces the same physics capabilities at HL-LHC as were achieved for Run 2, despite the increased pileup. The one exception for some of the measurements is muons, where an improved momentum resolution is anticipated. The baseline scenario for the expected systematic uncertainties assumes a reduction of many uncertainties compared to the extrapolated analyses. As a conservative benchmark, the results with Run 2 systematic uncertainty values are given as well. A similar exercise is also done for the Higgs boson mass measurement expected at HL-LHC.