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


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Tumasyan A., Adam W., Andrejkovic J., Bergauer T., Chatterjee S., Damanakis K., ...More

Nature Physics, vol.19, no.3, pp.338-350, 2023 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 19 Issue: 3
  • Publication Date: 2023
  • Doi Number: 10.1038/s41567-022-01838-y
  • Journal Name: Nature Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, Compendex, INSPEC
  • Page Numbers: pp.338-350
  • Hacettepe University Affiliated: Yes

Abstract

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/ψ 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/ψ 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/ψ 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.