Measurement of $J/\psi$-pair production in $pp$ collisions at $\sqrt{s}=13$ TeV and study of gluon transverse-momentum dependent PDFs

Abstract

The production cross-section of $J/\psi$ pairs in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ 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 $J/\psi$ mesons in the transverse momentum range $0<p_{\text{T}}<14$ GeV/$c$ and rapidity range $2.0<y<4.5$. The cross-section of this process is measured to be 16.36$\pm$0.28(stat)$\pm$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 $\Delta y$ between the two $J/\psi$ mesons. The effective cross-section of double-parton scattering is measured to be ${\sigma }_{\text{eff}}=$13.1$\pm$1.8(stat)$\pm$2.3(syst) mb. The distribution of the azimuthal angle ${\varphi }_{\text{CS}}$ of one of the $J/\psi$ mesons in the Collins-Soper frame and the $p_{\text{T}}$-spectrum of the $J/\psi$ pairs are also measured for the study of the gluon transverse-momentum dependent distributions inside protons. The extracted values of $⟨\cos 2{\varphi }_{\text{CS}}⟩$ and $⟨\cos 4{\varphi }_{\text{CS}}⟩$ are consistent with zero, but the presence of azimuthal asymmetry at a few percent level is allowed.

arXiv commentAll figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-022.html (LHCb public pages)

References in corpus (31)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• A Brief Introduction to PYTHIA 8.1
• Rigorous QCD Analysis of Inclusive Annihilation and Production of Heavy Quarkonium
• LHCb Detector Performance
• sPlot: a statistical tool to unfold data distributions
• Kernel Estimation in High-Energy Physics
• Color-octet quarkonia production
• Universality of Unintegrated Gluon Distributions at small x
• Color-octet quarkonia production II
• Transverse momentum dependence in gluon distribution and fragmentation functions
• Measurement of the track reconstruction efficiency at LHCb
• Precision luminosity measurements at LHCb
• Soft and Collinear Factorization and Transverse Momentum Dependent Parton Distribution Functions
• HELAC-Onia: an automatic matrix element generator for heavy quarkonium physics
• Physics Opportunities of a Fixed-Target Experiment using the LHC Beams
• Pair production of J/psi as a probe of double parton scattering at LHCb
• J/psi-Pair Production at Large Momenta: Indications for Double-Parton Scatterings and Large alpha_s^5 Contributions
• Performance of the Muon Identification at LHCb
• Proton Structure in Transverse Space and the Effective Cross Section
• Impact of $J/\psi$ pair production at the LHC and predictions in nonrelativistic QCD
• Pinning down the linearly-polarised gluons inside unpolarised protons using quarkonium-pair production at the LHC
• Scale Factor in Double Parton Collisions and Parton Densities in Transverse Space
• $B\bar{B}$ angular correlations at the LHC in parton Reggeization approach merged with higher-order matrix elements
• Studies of gluon TMDs and their evolution using quarkonium-pair production at the LHC
• Associated production of a quarkonium and a Z boson at one loop in a quark-hadron-duality approach
• Complete Study of Hadroproduction of a ${\rm Y}$ Meson Associated with a Prompt $J/\psi$
• Minijets and the Two-Body Parton Correlation
• Indication for Double Parton Scatterings in W + Prompt J/Psi Production at the LHC
• Tomography of pions and protons via transverse momentum dependent distributions
• $J/\psi$ meson production in association with an open charm hadron at the LHC: A reappraisal

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