Projected sensitivity of measurements of Higgs boson pair production with the ATLAS experiment at the HL-LHC

Prospects for the sensitivity of measurements to Higgs boson pair production with the ATLAS detector at the High Luminosity LHC (HL-LHC) are presented, obtained from a statistical combination of extrapolated results from six analyses of the Run 2 dataset, that used 126–140 fb^−1 of data at s = 13 TeV. Under the baseline extrapolation scenario for an integrated luminosity of 3000 fb^−1 at s = 14 TeV, the discovery significance of Standard Model Higgs boson pair production is found to be 4. 26, increasing to 5. 98 if systematic uncertainties are neglected. In the baseline scenario, the self-coupling strength modifier, κ_, is expected to be measured as 1. 0^+0. 48-₀. ₄₂, and the ₂ₕ coupling modifier affecting the interaction between two Higgs bosons and two vector bosons is expected to be measured as 1. 0^+0. 18-₀. ₁₅. These results represent a substantially improved outlook for HH production at the HL-LHC compared to previous studies.