ATLAS collaboration (2916 authors)Aguilar Saavedra, Juan AntonioAmor Dos Santos, Susana PatriciaAraque Espinosa, Juan PedroCastro, Nuno FilipeConde Muino, PatriciaDa Cunha Sargedas De Sousa, Mario JoseDias DO Vale, TiagoFaisca Rodrigues Pereira, Rui MiguelFiolhais, MiguelGalhardo, BrunoGomes, AgostinhoGoncalo, RicardoJorge, PedroMachado Miguens, JoanaMaio, AmeliaManeira, JoseMendes Gouveia, Emanuel DemetrioOleiro Seabra, Luis FilipeOnofre, AntonioCosta Batalha Pedro, RutePereira Peixoto, Ana PaulaSantos, HelenaSaraiva, JoaoSilva, Jose ManuelTavares Delgado, AdemarVeloso, FilipeWolters, Helmut2019-02-052019-02-052018-11-10http://dx.doi.org/10.1016/j.physletb.2018.09.024http://hdl.handle.net/10400.26/27676Searches for the exclusive decays of the Higgs and Z bosons into a J/ψ , ψ(2S) , or ϒ(nS) ( n=1,2,3 ) meson and a photon are performed with a pp collision data sample corresponding to an integrated luminosity of 36.1fb−1 collected at s=13TeV with the ATLAS detector at the CERN Large Hadron Collider. No significant excess of events is observed above the expected backgrounds, and 95% confidence-level upper limits on the branching fractions of the Higgs boson decays to J/ψγ , ψ(2S)γ , and ϒ(nS)γ of 3.5×10−4 , 2.0×10−3 , and (4.9,5.9,5.7)×10−4 , respectively, are obtained assuming Standard Model production. The corresponding 95% confidence-level upper limits for the branching fractions of the Z boson decays are 2.3×10−6 , 4.5×10−6 and (2.8,1.7,4.8)×10−6 , respectively.engjournal article2019-02-05