Comerma Montells, AlbertGarcia Moreno, PaulaGarrido Beltrán, LluísGioventù, AlessandraGironella Gironell, PereGomez Fernandez, SergioGraugés Pous, EugeniLobo Salvia, AniolLópez Huertas, AlbertManera Escalero, RafelMarin Benito, CarlaMauricio Ferre, JoanAlfonso Albero, AlejandroVazquez Gomez, RicardoLHCb Collaboration2025-06-272025-06-2720241126-6708https://hdl.handle.net/2445/221847The ratio of production cross-sections of ψ(2S) over J/ψ mesons as a function of charged-particle multiplicity in proton-proton collisions at a centre-of-mass energy √ s = 13 TeV is measured with a data sample collected by the LHCb detector, corresponding to an integrated luminosity of 658 pb−1 . The ratio is measured for both prompt and non-prompt ψ(2S) and J/ψ mesons. When there is an overlap between the rapidity ranges over which multiplicity and charmonia production are measured, a multiplicity-dependent modifcation of the ratio is observed for prompt mesons. No signifcant multiplicity dependence is found when the ranges do not overlap. For non-prompt production, the ψ(2S)-to-J/ψ production ratio is roughly independent of multiplicity, irrespective of the rapidity range over which the multiplicity is measured. The results are compared to predictions of the co-mover model and agree well except in the low multiplicity region. The ratio of production cross-sections of ψ(2S) over J/ψ mesons are cross-checked with other measurements in di-lepton channels and found to be compatible. 34 p.application/pdfengcc-by (c) Aaij, R. et al., 2024http://creativecommons.org/licenses/by/4.0/Col·lisions d'ions pesatsHadronsFísica de partículesHeavy ion collisionHadronsParticle physicsinfo:eu-repo/semantics/article7564662025-06-27info:eu-repo/semantics/openAccess