TY  - JOUR
AU  - LHCb Collaboration (Aaij, R. et al
AU  - Jaimes Elles, S. J.
AU  - Jashal, B. K.
AU  - Martinez-Vidal, F.
AU  - Oyanguren, A.
AU  - Rebollo De Miguel, M.
AU  - Sanderswood, I.
AU  - Zhuo, J.
PY  - 2024
DA  - 2024//
TI  - Measurement of J/ψ-pair production in pp collisions at √s=13 TeV and study of gluon transverse-momentum dependent PDFs
T2  - J. High Energy Phys.
JO  - Journal of High Energy Physics
SP  - 088
EP  - 40pp
VL  - 03
IS  - 3
PB  - Springer
KW  - Hadron-Hadron Scattering
KW  - Multi-Parton Interactions
KW  - QCD
KW  - Quarkonium
AB  - The production cross-section of J/psi pairs in proton-proton collisions at a centre-of-mass energy of root s = 13TeV 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(T) < 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 Delta y between the two J/psi mesons. The effective cross-section of double-parton scattering is measured to be sigma(eff) = 13.1 +/- 1.8 (stat) +/- 2.3 (syst) mb. The distribution of the azimuthal angle phi(CS) of one of the J/psi mesons in the Collins-Soper frame and the p(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 < cos4 phi(CS)> and < cos2 phi(CS)> are consistent with zero, but the presence of azimuthal asymmetry at a few percent level is allowed.
SN  - 1029-8479
UR  - https://arxiv.org/abs/2311.14085
UR  - https://doi.org/10.1007/JHEP03(2024)088
DO  - 10.1007/JHEP03(2024)088
LA  - English
N1  - WOS:001194594600001
ID  - LHCbCollaborationAaij_etal2024
ER  -