The observation of Higgs boson production in association with a top quark pair (tt¯H), based on the analysis of proton–proton collision data at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider, is presented. Using data corresponding to integrated luminosities of up to 79.8 fb−1, and considering Higgs boson decays into bb¯, WW⁎, τ+τ−, γγ, and ZZ⁎, the observed significance is 5.8 standard deviations, compared to an expectation of 4.9 standard deviations. Combined with the tt¯H searches using a dataset corresponding to integrated luminosities of 4.5 fb−1 at 7 TeV and 20.3 fb−1 at 8 TeV, the observed (expected) significance is 6.3 (5.1) standard deviations. Assuming Standard Model branching fractions, the total tt¯H production cross section at 13 TeV is measured to be 670 ± 90 (stat.) −100+110 (syst.) fb, in agreement with the Standard Model prediction.
- p p: scattering | p p: colliding beams | top: pair production | Higgs particle: associated production | Higgs particle: decay modes | bottom: pair production | W: pair production | Z0: pair production | tau: pair production | photon: pair production | Higgs particle: coupling | coupling: Yukawa | CERN LHC Coll | ATLAS | mass spectrum: two-photon | mass spectrum: (4lepton) | Higgs particle: branching ratio | total cross section: measured | experimental results | 13000 GeV-cms