Hayrapetyan, A.Tumasyan, A.Adam, W.Andrejkovic, J. W.Bergauer, T.Chatterjee, S.Damanakis, K.2025-03-232025-03-2320240031-90071079-7114https://doi.org/10.1103/PhysRevLett.132.121901https://hdl.handle.net/11486/5465The observation of WW gamma production in proton -proton collisions at a center -of -mass energy of 13 TeV with an integrated luminosity of 138 fb-1 is presented. The observed (expected) significance is 5.6 (5.1) standard deviations. Events are selected by requiring exactly two leptons (one electron and one muon) of opposite charge, moderate missing transverse momentum, and a photon. The measured fiducial cross section for WW gamma is 5.9 +/- 0.8(stat) +/- 0.8(syst) +/- 0.7(modeling) fb, in agreement with the next -to -leading order quantum chromodynamics prediction. The analysis is extended with a search for the associated production of the Higgs boson and a photon, which is generated by a coupling of the Higgs boson to light quarks. The result is used to constrain the Higgs boson couplings to light quarks.eninfo:eu-repo/semantics/openAccessHiggs-BosonArticle1321210.1103/PhysRevLett.132.121901385792072-s2.0-85188337355Q1WOS:001202254700005Q1