Aad G.Abbott B.Abeling K.Abicht N. J.Abidi S. H.Aboulhorma A.Abramowicz H.Abreu H.Abulaiti Y.Abusleme Hoffman A. C.Acharya B. S.Bourdarios C. AdamAdamczyk L.Adamek L.Addepalli S. VAddison M. J.Adelman J.Adiguzel A.Adye T.Affolder A. A.Afik Y.Agaras M. N.Agarwala J.Aggarwal A.Agheorghiesei C.Ahmad A.Ahmadov F.Ahmed W. S.Ahuja S.Ai X.Aielli G.Tamlihat M. AitAitbenchikh B.Aizenberg IAkbiyik M.Akesson T. P. A.Akimov A. VAkiyama D.Akolkar N. N.Al Khoury K.2025-05-192025-05-192024/01/010370-2693http://dx.doi.org/10.1016/j.physletb.2023.138400https://publicacionesabiertas.userena.cl/handle/123456789/235This letter reports the observation of () production in proton-proton collisions. This measurement uses the full Run 2 sample of events recorded at a center-of-mass energy of root= 13 TeV by the ATLAS detector at the LHC, corresponding to an integrated luminosity of 140 fb-1. Events with a leptonically-decaying boson and at least two photons are considered. The background-only hypothesis is rejected with an observed and expected significance of 5.6 standard deviations. The inclusive fiducial production cross section of () and () events is measured to be fid = 13.8 +/- 1.1(stat)+2.1-2.0(syst) +/- 0.1(lumi) fb, in agreement with the Standard Model prediction.Article