PT Journal AU ATLAS Collaboration (Aaboud, Mea Alvarez Piqueras, D Aparisi Pozo, JA Bailey, AJ Barranco Navarro, L Cabrera Urban, S Castillo, FL Castillo Gimenez, V Cerda Alberich, L Costa, MJ Escobar, C Estrada Pastor, O Ferrer, A Fiorini, L Fullana Torregrosa, E Fuster, J Garcia, C Garcia Navarro, JE Gonzalez de la Hoz, S Higon-Rodriguez, E Jimenez Pena, J Lacasta, C Lozano Bahilo, JJ Madaffari, D Mamuzic, J Marti-Garcia, S Melini, D Miñano, M Mitsou, VA Rodriguez Bosca, S Rodriguez Rodriguez, D Ruiz-Martinez, A Salt, J Santra, A Soldevila, U Sanchez, J Valero, A Valls Ferrer, JA Vos, M TI Searches for exclusive Higgs and Z boson decays into J/psi gamma, psi (2S) gamma, and Upsilon(nS) gamma at root s=13 TeV with the ATLAS detector SO Physics Letters B JI Phys. Lett. B PY 2018 BP 134 EP 155 VL 786 DI 10.1016/j.physletb.2018.09.024 LA English AB Searches for the exclusive decays of the Higgs and Z bosons into a J/psi, psi(2S), or Upsilon(nS) (n = 1, 2, 3) meson and a photon are performed with a pp collision data sample corresponding to an integrated luminosity of 36.1 fb(-1) collected at root s = 13 TeV 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/psi gamma, psi(2S) gamma and Upsilon(nS) gamma of 3.5 x 10(-4), 2.0 x 10(-3), and (4.9, 5.9, 5.7) x 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 x 10(-6), 4.5 x 10(-6) and (2.8, 1.7, 4.8) 10(-6), respectively. ER