@article{10902/32546, year = {2023}, month = {3}, url = {https://hdl.handle.net/10902/32546}, 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+141 −104 (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, doubleand triple-parton scattering are the dominant contributions for the measured process.}, publisher = {Nature Publishing Group}, publisher = {Nature Physics, 2023, 19(3), 338-350}, title = {Observation of triple J/φ meson production in proton-proton collisions}, author = {Tumasyan A and Brochero Cifuentes, Javier Andrés and Cabrillo Bartolomé, José Iban and Calderón Tazón, Alicia and Duarte Campderros, Jorge and Fernández García, Marcos and Fernández Madrazo, Celia and Fernández Manteca, Pedro José and García Alonso, Andrea and Gómez Gramuglio, Gervasio and Martínez Rivero, Celso and Martínez Ruiz del Árbol, Pablo and Matorras Weinig, Francisco and Matorras Cuevas, Pablo and Piedra Gómez, Jonatan and Prieëls, Cedric and Ruiz Jimeno, Alberto and Scodellaro, Luca and Vila Álvarez, Iván and Vizán García, Jesús Manuel}, }