Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector

M Aaboud, Torsten Åkesson, Simona Bocchetta, Eric Corrigan, Caterina Doglioni, Kristian Gregersen, Eva Brottmann Hansen, Vincent Hedberg, Göran Jarlskog, Charles Kalderon, Edgar Kellermann, Balazs Konya, Else Lytken, Katja Mankinen, Ulf Mjörnmark, Ruth Pöttgen, Trine Poulsen, Oxana Smirnova, ATLAS Collaboration