Tumasyan, A.Adam, W.Andrejkovic, J. W.Bergauer, T.Chatterjee, S.Damanakis, K.Dragicevic, M.2024-06-132024-06-1320230031-90071079-711410.1103/PhysRevLett.131.1518032-s2.0-85175275979https://doi.org/10.1103/PhysRevLett.131.151803https://hdl.handle.net/11501/1279We present an observation of photon-photon production of t lepton pairs in ultraperipheral lead-lead collisions. The measurement is based on a data sample with an integrated luminosity of 404 mu b(-1) collected by the CMS experiment at a center-of-mass energy per nucleon pair of root s(NN) = 5.02 TeV. The gamma gamma -> tau(+)tau(-) process is observed for tau(+)tau(-) events with a muon and three charged hadrons in the final state. The measured fiducial cross section is sigma(gamma gamma ->tau(+)tau(-)) = 4.8 +/- 0.6(stat) +/- 0.5(syst) mu b, where the second (third) term corresponds to the statistical (systematic) uncertainty in sigma(gamma gamma ->tau(+)tau(-)) in agreement with leading-order QED predictions. Using sigma(gamma gamma ->tau(+)tau(-)), we estimate a model-dependent value of the anomalous magnetic moment of the t lepton of at a(tau) = 0.001(-0.089)(+0.055).eninfo:eu-repo/semantics/openAccessArticle1537897747Q1131WOS:001096935800001N/A