Aad, GeorgesAbbott, BradenAbeling, KiraBeddall, Andrew JohnÇetin, Serkant AliÖztürk, SertaçŞimşek, Sinem2024-08-202024-08-202023Aad, G., Abbott, B., Abeling, K., Abicht, N. J., Abidi, S. H., Aboulhorma, A., & Abramowicz, H. (2023). Observation of an excess of dicharmonium events in the four-muon final state with the ATLAS detector. Physical review letters.0031-90071079-7114https://hdl.handle.net/20.500.12713/5980A search is made for potential ccc over bar c over bar tetraquarks decaying into a pair of charmonium states in the four ffiffi muon final state using proton-proton collision data at p s = 13 TeV, corresponding to an integrated luminosity of 140 fb-1 recorded by the ATLAS experiment at LHC. Two decay channels, J lig +J lig -4 mu and J lig + ig(2S) -4 mu, are studied. Backgrounds are estimated based on a hybrid approach involving Monte Carlo simulations and data-driven methods. Statistically significant excesses with respect to backgrounds dominated by the single parton scattering are seen in the di-J lig channel consistent with a narrow resonance at 6.9 GeV and a broader structure at lower mass. A statistically significant excess is also seen in the J lig + ig(2S) channel. The fitted masses and decay widths of the structures are reported.eninfo:eu-repo/semantics/openAccessDouble-Parton ScatteringsJ/PSI-Pair ProductionArticle1311530339442WOS:0011029017000012-s2.0-85175279527Q110.1103/PhysRevLett.131.151902Q1