Electromagnetic processes with quasireal photons in Pb+Pb collisions: QED, QCD, and the QGP Steinberg, Peter Aguilar Saavedra, Juan Antonio Atlas Collaboration Electromagnetic processes, both photon-photon and photon-nucleus, are shown to be useful in studying aspects of QED, QCD, and potentially the QGP. Using lead-lead collisions at √ sNN = 5.02 TeV, the ATLAS detector has performed measurements of exclusive dimuon production, light-by-light scattering (via exclusive diphoton production), and photo-nuclear dijet production. These are all important examples of ultraperipheral collisions, where the nuclei do not interact hadronically. A recent study of the opening angles of dimuons produced in hadronic heavy-ion collisions, after subtracting heavy-flavor backgrounds, demonstrates that the dimuons carry information correlated with the overlap geometry, potentially about the density of charges in the QGP itself. 2020-02-14T11:45:07Z 2020-02-14T11:45:07Z 2019 info:eu-repo/semantics/article Steinberg, P. (2019). Electromagnetic processes with quasireal photons in Pb+ Pb collisions: QED, QCD, and the QGP. Nuclear Physics A, 982, 259-262. http://hdl.handle.net/10481/59679 10.1016/j.nuclphysa.2018.10.087 eng http://creativecommons.org/licenses/by-nc-nd/3.0/es/ info:eu-repo/semantics/openAccess Atribución-NoComercial-SinDerivadas 3.0 España Elsevier BV