Aaboud, M.Albert, JustinChiu, Y. H.Elliot, Alison A.Fincke-Keeler, J.Hamano, KenjiHill, Ewan ChinKeeler, RichardKowalewski, RobertKuwertz, E. S.Kwan, TonyLeBlanc, Matthew EdgarLefebvre, MichelMcPherson, Robert A.Seuster, RolfSobie, Randall J.Trovatelli, M.Venturi, M.ATLAS Collaboration2020-02-182020-02-1820172017Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Abeloos, B.; Abidi, S. H.; … & Zwalinski, L. (2017). Search for Heavy Higgs Bosons A/H Decaying to a Top Quark Pair in pp Collisions at √s=8 TeV with the ATLAS Detector. Physical Review Letters, 119(19), article 191803. DOI: 10.1103/PhysRevLett.119.191803https://doi.org/10.1103/PhysRevLett.119.191803http://hdl.handle.net/1828/11574A search for heavy pseudoscalar (A) and scalar (H) Higgs bosons decaying into a top quark pair (t¯t) has been performed with 20.3  fb−1 of proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider at a center-of-mass energy √s=8  TeV. Interference effects between the signal process and standard model t¯t production, which are expected to distort the signal shape from a single peak to a peak-dip structure, are taken into account. No significant deviation from the standard model prediction is observed in the t¯t invariant mass spectrum in final states with an electron or muon, large missing transverse momentum, and at least four jets. The results are interpreted within the context of a type-II two-Higgs-doublet model. Exclusion limits on the signal strength are derived as a function of the mass mA/H and the ratio of the vacuum expectation values of the two Higgs fields, tanβ, for mA/H>500  GeV.enExtensions of Higgs sectorHypothetical particle physics modelsHypothetical scalarsTop quarkHadron collidersArticleDepartment of Physics and Astronomy