Tumasyan, A.Adam, W.Andrejkovic, J. W.Bergauer, T.Chatterjee, S.Dragicevic, M.The ATLAS collaboration2024-03-092024-03-0920230031-90071079-7114https://doi.org/10.1103/PhysRevLett.131.091803https://hdl.handle.net/20.500.14034/1378The first observation of the production of (WW +/-)-W-+/- bosons from double parton scattering processes using same-sign electron-muon and dimuon events in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of 138 fb(-1) recorded at a center-of-mass energy of 13 TeV using the CMS detector at the CERN LHC. Multivariate discriminants are used to distinguish the signal process from the main backgrounds. A binned maximum likelihood fit is performed to extract the signal cross section. The measured cross section for production of same-sign W bosons decaying leptonically is 80.7 +/- 11.2(stat) (+9.5)(-8.6)(syst) +/- 12.1(model) fb, whereas the measured fiducial cross section is 6.28 +/- 0.81(stat) +/- 0.69(syst) +/- 0.37(model) fb. The observed significance of the signal is 6.2 standard deviations above the background-only hypothesis.eninfo:eu-repo/semantics/openAccessArticle10.1103/PhysRevLett.131.0918031319N/AWOS:0011027172000012-s2.0-8517169721537721845Q1