Inclusive production of J/ψ and ψ′ mesons at the LHC
1 University of Rzeszów, PL-35-959 Rzeszów, Poland
2 Institute of Nuclear Physics PAN, PL-31-342 Cracow, Poland
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Published online: 29 November 2016
We discuss the prompt production of J/ψ mesons in proton-proton collisions at the LHC within a NRQCD kt-factorization approach using Kimber-Martin-Ryskin (KMR) unintegrated gluon distributions (UGDF). We include both direct color-singlet production (gg → J/ψg) as well as a feed-down from χc → J/ψγ and ψ′ → J/ψX. The production of the decaying mesons (χc or ψ′) is also calculated within NRQCD ktfactorization. The corresponding matrix elements for gg → J/ψ, gg → ψ′ and gg → χc include parameters of the nonrelativistic spatial wave functions of quarkonia at r = 0, which are taken from potential models from the literature. We get the ratio of the corresponding of the cross sections for χc(2)-to-χc(1) much closer to experimental data than obtained in recent analyses. Differential distributions in rapidity of J/ψ and ψ′ are calculated and compared to experimental data of the ALICE and LHCb collaborations. We discuss possible onset of gluon saturation effects at forward/backward rapidities. One can describe the experimental data for J/ψ production within model uncertainties with color-singlet component only. Therefore our theoretical results leave only a relatively small room for the color-octet contributions.
© The Authors, published by EDP Sciences, 2016
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