Observation of structures in the J/ψ + ψ(2S) mass spectrum with the ATLAS detector



Aad, G, Aakvaag, E, Abbott, B, Abdelhameed, S, Abeling, K, Abicht, NJ, Abidi, SH, Aboelela, M, Aboulhorma, A, Abramowicz, H
et al (show 2864 more authors) (2026) Observation of structures in the J/ψ + ψ(2S) mass spectrum with the ATLAS detector PHYSICAL REVIEW D, 113 (11). 112015-. ISSN 2470-0010, 2470-0029

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Abstract

A search for resonant structures in the J / ψ + ψ ( 2 S ) mass spectrum is performed using proton-proton collision data at s = 13 TeV , corresponding to an integrated luminosity of 140 fb − 1 , recorded by the ATLAS experiment at the LHC. The decay channels of J / ψ + ψ ( 2 S ) → 4 μ and J / ψ + ψ ( 2 S ) → 4 μ + 2 π are analyzed. An excess near 6.9 GeV is observed in both channels with a combined significance of 8.9 σ . No significant signal is observed near 7.2 GeV, and an upper limit on its yield relative to X ( 6900 ) is provided. A simultaneous fit with the di- J / ψ channel is carried out under assumptions regarding the resonance interferences, yielding a ratio of the partial decay widths between the J / ψ + ψ ( 2 S ) and di- J / ψ channels of 1.08 ± 0.2 0 − 0.17 + 0.40 for the resonance near 6.9 GeV.

Item Type: Article
Uncontrolled Keywords: 5107 Particle and High Energy Physics, 5101 Astronomical Sciences, 51 Physical Sciences
Divisions: Faculty of Science & Engineering
Faculty of Science & Engineering > School of Physical Sciences
Faculty of Science & Engineering > School of Physical Sciences > Physics
Depositing User: Symplectic Admin
Date Deposited: 27 Jul 2026 07:56
Last Modified: 03 Aug 2026 13:24
DOI: 10.1103/zhkx-k9zl
Open Access URL: https://journals.aps.org/prd/abstract/10.1103/zhkx...
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URI: https://livrepository.liverpool.ac.uk/id/eprint/3199549
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