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 4.26σ, increasing to 5.98σ if systematic uncertainties are neglected. In the baseline scenario, the self-coupling strength modifier, κλ, is expected to be measured as 1.0+0.48-0.42, and the κ2V 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.