Combination of searches for resonant Higgs boson pair production using pp collisions at √s=13 TeV with the ATLAS detector ; Combination of searches for resonant Higgs boson pair production using pp collisions at [square root]s=13 TeV with the ATLAS detector

A combination of searches for a new resonance decaying into a Higgs boson pair is presented, using up to 139 fb−1 of ⁢ collision data at √ =13 TeV recorded with the ATLAS detector at the LHC. The combination includes searches performed in three decay channels: ⁢¯ ⁢ ¯ , ¯ ⁢ +⁢ −, and ¯ ⁢ ⁢ . No excess above the expected Standard Model background is observed and upper limits are set at the 95% confidence level on the production cross section of Higgs boson pairs originating from the decay of a narrow scalar resonance with mass in the range 251 GeV–5 TeV. The observed (expected) limits are in the range 0.96–600 fb (1.2–390 fb). The limits are interpreted in the type-I two-Higgs-doublet model and the minimal supersymmetric standard model, and constrain parameter space not previously excluded by other searches.