Measurement of J/ψ-pair production in pp collisions at $$ \sqrt{s} $$ = 13 TeV and study of gluon transverse-momentum dependent PDFs
Author(s)
Aaij, R.; Abdelmotteleb, A. S. W.; Abellan Beteta, C.; Abudinén, F.; Ackernley, T.; Adeva, B.; Adinolfi, M.; Adlarson, P.; Afsharnia, H.; Agapopoulou, C.; Aidala, C. A.; Ajaltouni, Z.; Akar, S.; Akiba, K.; Albicocco, P.; Albrecht, J.; ... Show more Show less
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The production cross-section of J/ψ pairs in proton-proton collisions at a centre-of-mass energy of
s
$$ \sqrt{s} $$
= 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.
Date issued
2024-03-14Department
Massachusetts Institute of Technology. Department of PhysicsJournal
Journal of High Energy Physics
Publisher
Springer Berlin Heidelberg
Citation
Journal of High Energy Physics. 2024 Mar 14;2024(3):88
Version: Final published version
ISSN
1029-8479
Keywords
Nuclear and High Energy Physics