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 Collaboration2020-02-282020-02-2820172017Aaboud, M.; Aad, G.; Abbott, B.; Abdinov, O.; Abeloos, B.; Abidi, S. H.; … & Zwalinski, L. (2017). Searches for the Zγ decay mode of the Higgs boson and for new high-mass resonances in pp collisions at √s=13 TeV with the ATLAS detector. Journal of High Energy Physics, 2017(10), article 112. DOI: 10.1007/JHEP10(2017)112https://doi.org/10.1007/JHEP10(2017)112http://hdl.handle.net/1828/11589This article presents searches for the Zγ decay of the Higgs boson and for narrow high-mass resonances decaying to Zγ, exploiting Z boson decays to pairs of electrons or muons. The data analysis uses 36.1 fb−1 of pp collisions at s√=13 recorded by the ATLAS detector at the CERN Large Hadron Collider. The data are found to be consistent with the expected Standard Model background. The observed (expected — assuming Standard Model pp → H → Zγ production and decay) upper limit on the production cross section times the branching ratio for pp → H → Zγ is 6.6. (5.2) times the Standard Model prediction at the 95% confidence level for a Higgs boson mass of 125.09 GeV. In addition, upper limits are set on the production cross section times the branching ratio as a function of the mass of a narrow resonance between 250 GeV and 2.4 TeV, assuming spin-0 resonances produced via gluon-gluon fusion, and spin-2 resonances produced via gluon-gluon or quark-antiquark initial states. For high-mass spin-0 resonances, the observed (expected) limits vary between 88 fb (61 fb) and 2.8 fb (2.7 fb) for the mass range from 250 GeV to 2.4 TeV at the 95% confidence level.enHadron-Hadron scattering (experiments)Higgs physicsArticleDepartment of Physics and Astronomy