Study of the rare decay $J/\psi \to \mu^+\mu^-\mu^+\mu^-

• Main Authors: Albrecht, J, Amey, J. L, Anderlini, L, Ao, D, Da Silva, R. Ataíde, Bachmann, S, Basels, J. M, Belyaev, I, Blake, T, Bolzonella, R, Borsato, M, Rodriguez, A. Brea, Brown, J, Buonaura, A, Carniti, P, Chobanova, V, Chulikov, V, Collins, P, Contu, A, Daniel, J, De Lucia, E, de Vries, J. A, Delaney, B, Didenko, S, Dobishuk, V, Donohoe, A. M, Egorychev, A, Epple, E, Esen, S, Feng, M, Feo, M, Gomez, M. Fernandez, Sevilla, M. Franco, Friday, D. A, Gabriel, E, Gandini, P, Martin, L. M. Garcia, Garrido, L, Giovannetti, M, Cardoso, L. A. Granado, Hemmer, F, Hunter, R. J, Jones, T. P, Jost, B, Khanji, B, Kozachuk, A, Krzemien, W, Leroy, O, Castro, J. Lomba, Maisuzenko, D, Manca, G, Martellotti, G, Matteuzzi, C, Garcia, L. Meyer, Miao, H, Muhammad, E, Muñoz-Rojas, F, Murta, R, Naik, P, Nicolini, J, Nicotra, D, O'Neil, R. H, Pais, P. R, Pajero, T, Petrolini, A, Piccini, M, Pietrzyk, G, Polycarpo, E, Qu, S, Rangel, M. S, De Miguel, M. Rebollo, Sahoo, D, Santovetti, E, Sazak, H, Schulte, N, Schwemmer, R, Song, Y, Stahl, M, Strekalina, D, Tisserand, V, Ustyuzhanin, A, Vecchi, S, Vos, K, Vouters, G, Wan, G, Wang, R, Wang, X, Wang, Y, Wang, Z, Westhenry, B. D. C, White, C, Xiang, Z, Xu, A, Zhang, S, Zhao, Y, Zhou, X, Zhou, Y, Zhovkovska, V, Zhu, L. Z, Zhuo, J
• Format: Journal Article
• Language: English
• Published: 29.08.2024
• Subjects: Physics - High Energy Physics - Experiment
• DOI: 10.48550/arxiv.2408.16646

The rare electromagnetic $J/\psi \to \mu^+\mu^-\mu^+\mu^-$ decay is observed with a significance greatly exceeding the discovery threshold, using proton-proton collision data collected by the LHCb experiment during 2016-2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of $5.4\,\text{fb}^{-1}$. The rate of this decay is measured relative to that of the $J/\psi \to \mu^+\mu^-$ mode. Using the QED model for the four-muon decay in the efficiency estimation, its branching fraction is determined to be \begin{equation*} {\mathcal{B}}(J/\psi \to \mu^+\mu^-\mu^+\mu^-) = (1.13\pm0.10\pm0.05\pm0.01)\times 10^{-6}, \end{equation*} where the uncertainties are statistical, systematic and due to the uncertainty on the branching fraction of the $J/\psi \to \mu^+\mu^-$ decay.