Measurement of J/ψ-pair production in pp collisions at s = 13 TeV and study of gluon transverse-momentum dependent PDFs

The LHCb Collaboration

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The production cross-section of J/ψ pairs in proton-proton collisions at a centre-of-mass energy of s = 13 TeV is measured using a data sample corresponding to an integrated luminosity of 4.2 fb−1 collected by the LHCb experiment. The measurement is performed with both J/ψ mesons in the transverse momentum range 0 < pT< 14 GeV/c and rapidity range 2.0 < y < 4.5. The cross-section of this process is measured to be 16.36 ± 0.28 (stat) ± 0.88 (syst) nb. The contributions from single-parton scattering and double-parton scattering are separated based on the dependence of the cross-section on the absolute rapidity difference ∆y between the two J/ψ mesons. The effective cross-section of double-parton scattering is measured to be σeff = 13.1 ± 1.8 (stat) ± 2.3 (syst) mb. The distribution of the azimuthal angle ϕCS of one of the J/ψ mesons in the Collins-Soper frame and the pT-spectrum of the J/ψ pairs are also measured for the study of the gluon transverse-momentum dependent distributions inside protons. The extracted values of ⟨cos 2ϕCS⟩ and ⟨cos 4ϕCS⟩ are consistent with zero, but the presence of azimuthal asymmetry at a few percent level is allowed.

Original languageEnglish
Article number88
Pages (from-to)1-40
Number of pages40
JournalJournal of High Energy Physics
Volume2024
Issue number3
Early online date14 Mar 2024
DOIs
Publication statusPublished - Mar 2024

Bibliographical note

Publisher Copyright:
© The Author(s) 2024.

Funding

We would like to thank J.-P. Lansberg, H.-S. Shao, Y.-Q. Ma and L.-P. Sun for the helpful discussions on the quarkonium and quarkonium-pair production, and J.-P. Lansberg, H.-S. Shao, D. Boer, J. Bor, A. Colpani Serri, Z.-G. He and M. A. Nefedov for providing the SPS calculations. We express our gratitude to our colleagues in the CERN accelerator departments for the excellent performance of the LHC. We thank the technical and administrative staff at the LHCb institutes. We acknowledge support from CERN and from the national agencies: CAPES, CNPq, FAPERJ and FINEP (Brazil); MOST and NSFC (China); CNRS/IN2P3 (France); BMBF, DFG and MPG (Germany); INFN (Italy); NWO (Netherlands); MNiSW and NCN (Poland); MCID/IFA (Romania); MICINN (Spain); SNSF and SER (Switzerland); NASU (Ukraine); STFC (United Kingdom); DOE NP and NSF (U.S.A.). We acknowledge the computing resources that are provided by CERN, IN2P3 (France), KIT and DESY (Germany), INFN (Italy), SURF (Netherlands), PIC (Spain), GridPP (United Kingdom), CSCS (Switzerland), IFIN-HH (Romania), CBPF (Brazil), and Polish WLCG (Poland). We are indebted to the communities behind the multiple open-source software packages on which we depend. Individual groups or members have received support from ARC and ARDC (Australia); Key Research Program of Frontier Sciences of CAS, CAS PIFI, CAS CCEPP, Fundamental Research Funds for the Central Universities, and Sci. & Tech. Program of Guangzhou (China); Minciencias (Colombia); EPLANET, Marie Sk\u0142odowska-Curie Actions, ERC and NextGenerationEU (European Union); A*MIDEX, ANR, IPhU and Labex P2IO, and R\u00E9gion Auvergne-Rh\u00F4ne-Alpes (France); AvH Foundation (Germany); ICSC (Italy); GVA, XuntaGal, GENCAT, Inditex, InTalent and Prog. Atracci\u00F3n Talento, CM (Spain); SRC (Sweden); the Leverhulme Trust, the Royal Society and UKRI (United Kingdom).

FundersFunder number
Institutul National de Cercetare-Dezvoltare pentru Fizica si Inginerie Nucleara 'Horia Hulubei'
Agence Nationale de la Recherche
Australian Research Council
Australian Research Data Commons
Stockholm Resilience Centre, Stockholm University
National Academy of Sciences of Ukraine
Narodowe Centrum Nauki
National Science Foundation
Institut national de physique nucléaire et de physique des particules
Science and Technology Facilities Council
H2020 Marie Skłodowska-Curie Actions
NextGenerationEU
Automotive Research Center
Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Ministerio de Ciencia e Innovación
Ministry of Science and Technology, Taiwan
Program of Guangzhou
Leverhulme Trust
SURF
Instituto Nazionale di Fisica Nucleare
Financiadora de Estudos e Projetos
Polish WLCG
Centre National de la Recherche Scientifique
Bundesministerium für Bildung und Forschung
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Karlsruhe Institute of Technology
Deutsche Forschungsgemeinschaft
Région Auvergne-Rhône-Alpes
U.S. Department of Energy
International Council of Shopping Centers
CAS CCEPP
GridPP
Deutsches Elektronen-Synchrotron
Chinese Academy of Sciences
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Key Research Program of Frontier Sciences of CAS
Royal Society
Sociedad Española de Reumatología
European Research Council
EPLANET
Ministerstwo Edukacji i Nauki
Generalitat Valenciana
CERN
Fundamental Research Funds for the Central Universities
Alexander von Humboldt-Stiftung
UK Research and Innovation
National Natural Science Foundation of China

    Keywords

    • Hadron-Hadron Scattering
    • Multi-Parton Interactions
    • QCD
    • Quarkonium

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