%0 Journal Article %T Observation of WWW Production in pp Collisions at p=13 TeV with the ATLAS Detector %A ATLAS Collaboration (Aad, G. et al %A Amos, K. R. %A Aparisi Pozo, J. A. %A Bailey, A. J. %A Cabrera Urban, S. %A Cardillo, F. %A Castillo Gimenez, V. %A Costa, M. J. %A Didenko %A Escobar, C. %A Fiorini, L. %A Fullana Torregrosa, E. %A Fuster, J. %A Garcia, C. %A Garcia Navarro, J. E. %A Gonzalez de la Hoz, S. %A Gonzalvo Rodriguez, G. R. %A Guerrero Rojas, J. G. R. %A Higon-Rodriguez, E. %A Lacasta, C. %A Lozano Bahilo, J. J. %A Mamuzic, J. %A Marti-Garcia, S. %A Martinez Agullo, P. %A Miralles Lopez, M. %A Mitsou, V. A. %A Monsonis Romero, L. %A Moreno Llacer, M. %A Navarro-Gonzalez, J. %A Poveda, J. %A Prades Ibañez, A. %A Ruiz-Martinez, A. %A Sabatini, P. %A Salt, J. %A Sanchez Sebastian, V. %A Sayago Galvan, I. %A Soldevila, U. %A Sanchez, J. %A Torro Pastor, E. %A Valero, A. %A Valls Ferrer, J. A. %A Villaplana Perez, M. %A Vos, M. %J Physical Review Letters %D 2022 %V 129 %N 6 %I Amer Physical Soc %@ 0031-9007 %G English %F ATLASCollaborationAad_etal2022 %O WOS:000842367600009 %O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=5341), last updated on Fri, 02 Sep 2022 07:29:43 +0000 %X This Letter reports the observation of WWW production and a measurement of its cross section using detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charged leptons, are selected. A multivariate technique is then used to discriminate between signal and background events. Events from WWW production are observed with a significance of 8.0 standard deviations, where the expectation is 5.4 standard deviations. The inclusive WWW production cross section is measured to be 820 ± 100 (stat) ± 80 (syst) fb, approximately 2.6 standard deviations from the predicted cross section of 511 ± 18 fb calculated at next-to-leading-order QCD and leading-order electroweak accuracy. %R 10.1103/PhysRevLett.129.061803 %U https://arxiv.org/abs/2201.13045 %U https://doi.org/10.1103/PhysRevLett.129.061803 %P 061803-20pp