Observation of triple J/psi meson production in proton-proton collisions

The CMS Collaboration, A. Tumasyan, W. Adam, P. Eerola, Laurent Forthomme, H. Kirschenmann, K. Österberg, M. Voutilainen, Shudhashil Bharthuar, Erik Brücken, F. Garcia, J. Havukainen, Jaana Heikkilä, Minsuk Kim, R. Kinnunen, T. Lampén, K. Lassila-Perini, S. Laurila, S. Lehti, T. LindénMikko Lotti, P. Luukka, Laura Martikainen, Mikael Erkki Johannes Myllymäki, Jennifer Ott, Juska Pekkanen, H. Siikonen, E. Tuominen, J. Tuominiemi, Jussi Viinikainen, H. Petrow, T. Tuuva

Research output: Contribution to journalArticleScientificpeer-review


Protons consist of three valence quarks, two up-quarks and one down-quark, held together by gluons and a sea of quark-antiquark pairs. Collectively, quarks and gluons are referred to as partons. In a proton-proton collision, typically only one parton of each proton undergoes a hard scattering - referred to as single-parton scattering - leaving the remainder of each proton only slightly disturbed. Here, we report the study of double- and triple-parton scatterings through the simultaneous production of three J/psi mesons, which consist of a charm quark-antiquark pair, in proton-proton collisions recorded with the CMS experiment at the Large Hadron Collider. We observed this process - reconstructed through the decays of J/psi mesons into pairs of oppositely charged muons - with a statistical significance above five standard deviations. We measured the inclusive fiducial cross-section to be 272(-104)(+141) (stat) +/- 17 (syst) fb, and compared it to theoretical expectations for triple-J/psi meson production in single-, double- and triple-parton scattering scenarios. Assuming factorization of multiple hard-scattering probabilities in terms of single-parton scattering cross-sections, double- and triple-parton scattering are the dominant contributions for the measured process.
Original languageEnglish
JournalNature Physics
Issue number3
Pages (from-to)338–350
Number of pages17
Publication statusPublished - Mar 2023
MoE publication typeA1 Journal article-refereed

Bibliographical note

A Publisher Correction to this article was published on 27 February 2023. https://doi.org/10.1038/s41567-023-01992-x

Fields of Science

  • 114 Physical sciences
  • Double parton interactions
  • P(p)over-bar collisions
  • Matrix-element
  • Jet events
  • Helac-onia
  • Scatterings
  • Generator
  • Pp

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