Combination of searches for resonant and non-resonant Higgs boson pair production in the bbyy, bbπ and bbbb decay channels using pp collisions at √s= 13 TeV with the ATLAS detectors

A combination of searches for Higgs boson pair production is performed using up to 139 fb$^{-1}$ of proton-proton collision data at a center-of-mass energy $\sqrt{s}=13$ TeV recorded with the ATLAS detector at the LHC. The combination exploits three analyses searching for $HH$ decays to $bb\gamma\gamma$, $bb\tau\tau$ and $bbbb$. Results are interpreted in the context of non-resonant and resonant Higgs boson pair production scenarios. In the non-resonant interpretation, upper limits are set on the Higgs boson pair production cross-section and on the self-coupling modifier $\kappa_\lambda$. In the resonant interpretation, upper limits are set on the Higgs boson pair production cross-section as a function of the heavy resonance mass.