Made available in DSpace on 2022-04-30T09:38:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-06-04; The observation of Higgs boson production in association with a top quark-antiquark pair is reported, based on a combined analysis of proton-proton collision data at center-of-mass energies of s=7, 8, and 13 TeV, corresponding to integrated luminosities of up to 5.1, 19.7, and 35.9 fb-1, respectively. T...