Observation of an Excess of Dicharmonium Events in the Four-Muon Final State with the ATLAS Detector

Summary, in English

A search is made for potential ccc[over ¯]c[over ¯] tetraquarks decaying into a pair of charmonium states in the four muon final state using proton-proton collision data at sqrt[s]=13 TeV, corresponding to an integrated luminosity of 140 fb^{-1} recorded by the ATLAS experiment at LHC. Two decay channels, J/ψ+J/ψ→4μ and J/ψ+ψ(2S)→4μ, 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/ψ 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/ψ+ψ(2S) channel. The fitted masses and decay widths of the structures are reported.

• Author: G. Aad; T.P.A. Åkesson; C. Doglioni; P.A. Ekman; V. Hedberg; H. Herde; B. Konya; E. Lytken; R. Poettgen; N.D. Simpson; E. Skorda; O. Smirnova; L. Zwalinski
• Department/s: Particle and nuclear physics; eSSENCE: The e-Science Collaboration
• Publishing year: 2023
• Language: English
• Publication/Series: Physical Review Letters
• Volume: 131
• Issue: 15
• Links: http://dx.doi.org/10.1103/PhysRevLett.131.151902
• Document type: Journal article
• Publisher: American Physical Society
• Topic: Subatomic Physics
• Keywords: article; luminance; Monte Carlo method
• Status: Published
• ISBN/ISSN/Other: ISSN: 1079-7114