Measurement prospects of Higgs boson pair production in the $b\bar{b}\gamma\gamma$ final state with the ATLAS experiment at the HL-LHC

A prospect study for the search for non-resonant Higgs boson pair production in the $b\bar{b}\gamma\gamma$ decay channel is presented, assuming 3000 $\text{fb}^{-1}$ of $pp$ collisions at $\sqrt{s}=14$ TeV with the ATLAS detector at the High Luminosity LHC (HL-LHC). The projected results are based on extrapolations of the Run 2 analysis conducted with 139 $\text{fb}^{-1}$ at $\sqrt{s}=13$ TeV. In addition to the increased luminosity and center-of-mass energy at the HL-LHC, both experimental and theoretical systematic uncertainties are expected to be reduced relative to their Run 2 values. The extrapolated precision on the signal strength measurement with (without) systematic uncertainties is 50% (46%), with a corresponding signal significance of $2.2 \sigma$ ($2.3 \sigma$). With (without) systematic uncertainties, $\kappa_\lambda$, the modifier of the trilinear Higgs boson self-coupling, is projected to be constrained to the $1 \sigma$ confidence interval $[0.3, 1.9]$ ($[0.4, 1.8]$) assuming Standard Model couplings at the HL-LHC. Without Higgs boson pair production, projected results exclude values of $\kappa_\lambda$ outside of [1.1, 4.3] ([1.2, 4.2]) at the 95% confidence level.