Measurement of the production cross section of three isolated photons in pp collisions at √s=8TeV using the ATLAS detector Aaboud, M. Aguilar Saavedra, Juan Antonio Atlas Collaboration Melini, Davide A measurement of the production of three isolated photons in proton–proton collisions at a centre-of-mass energy √s=8TeV is reported. The results are based on an integrated luminosity of 20.2fb−1collected with the ATLAS detector at the LHC. The differential cross sections are measured as functions of the transverse energy of each photon, the difference in azimuthal angle and in pseudorapidity between pairs of photons, the invariant mass of pairs of photons, and the invariant mass of the triphoton system. A measurement of the inclusive fiducial cross section is also reported. Next-to-leading-order perturbative QCD predictions are compared to the cross-section measurements. The predictions underestimate the measurement of the inclusive fiducial cross section and the differential measurements at low photon transverse energies and invariant masses. They provide adequate descriptions of the measurements at high values of the photon transverse energies, invariant mass of pairs of photons, and invariant mass of the triphoton system. 2018-09-20T11:06:06Z 2018-09-20T11:06:06Z 2018-03-23 journal article Aaboud, M.; Aguilar-Saavedra, Juan Antonio; Atlas Collaboration. Measurement of the production cross section of three isolated photons in pp collisions at √s=8TeV using the ATLAS detector. Physics Letters B 781 (2018) 55–76 [http://hdl.handle.net/10481/52816] http://hdl.handle.net/10481/52816 10.1016/j.physletb.2018.03.057 eng http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España Elsevier B. V.