Inclusive production of J/ψ and ψ′ mesons at the LHC

• Main Authors: Cisek Anna, Szczurek Antoni
• Format: Article
• Language: English
• Published: EDP Sciences 2016-01-01
• Series: EPJ Web of Conferences
• Online Access: http://dx.doi.org/10.1051/epjconf/201613005003

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.