Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Prompt inclusive production of $J/\psi$, $\psi'$ and $\chi_{c}$ mesons
  at the LHC in forward directions within the NRQCD $k_t$-factorization
  approach - search for the onset of gluon saturation   We discuss prompt production of $J/\psi$ mesons in proton-proton collisions
at the LHC within NRQCD $k_t$-factorization approach using Kimber-Martin-Ryskin
(KMR) unintegrated gluon distributions (UGDF). We include both direct
color-singlet production ($g g \to J/\psi g$) as well as a feed-down from
$\chi_c \to J/\psi \gamma$ and $\psi' \to J/\psi X$ decays. The production of
the decaying mesons ($\chi_c$ or $\psi'$) is also calculated within NRQCD
$k_t$-factorization approach. The corresponding matrix elements for $g g \to
J/\psi$ g, $g g \to \psi'g$ and $g g \to \chi_c$ include parameters of the
nonrelativistic space wave functions of the quarkonia at $r = 0$, which are
taken from potential models in the literature. We get the ratio of the
corresponding cross section ratio for $\chi_c(2)$-to-$\chi_c(1)$ at
midrapidities much closer to experimental data than obtained in a recent
analysis. Differential distributions in rapidity and transverse momentum of
$J/\psi$ and $\psi'$ are calculated and compared with experimental data of the
ALICE and LHCb collaborations. We discuss a possible onset of gluon saturation
effects in the production of $J/\psi$ and $\chi_{c}$ mesons at forward/backward
rapidities. We show that it is neccessary to modify the standard KMR UGDF to
describe ALICE and LHCb data. A mixed UGDF scenario was proposed. Then we can
describe the experimental data for $J/\psi$ production within model
uncertainties with color-singlet component only. Therefore our theoretical
results leave only a relatively small room for the color-octet contributions.

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The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
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The categories of this paper are: hep-lat
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The categories of this paper are: funct-an
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The categories of this paper are: cs
10
The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
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The categories of this paper are: math