Combination of searches for Higgs boson pair production in proton-proton collisions at $\sqrt{s} =$ 13 TeV
Phys.Rev.Lett. 122 (2019) 121803
The collaboration

Abstract (data abstract)
This Letter describes a search for Higgs boson pair production using the combined results from four final states: \bbgg, \bbtt, \bbbb, and \bbvv, where V represents a $\PW$ or \PZ boson. The search is performed using data collected in 2016 by the CMS experiment from LHC proton-proton collisions at $\sqrt{s} = 13\TeV$, corresponding to an integrated luminosity of 35.9\fbinv.Limits are set on the Higgs boson pair production cross section. A 95\% confidence level observed (expected) upper limit on the nonresonant production cross section is set at 22.2\,(12.8) times the standard model value.A search for narrow resonances decaying to Higgs boson pairs is also performed in the mass range 250--3000\GeV. No evidence for a signal is observed, and upper limits are set on the resonance production cross section.