Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Coherent $\psi$(2S) photo-production in ultra-peripheral Pb-Pb
  collisions at $\sqrt{s}_{\rm NN}$ = 2.76 TeV   We have has performed the first measurement of the coherent $\psi$(2S)
photo-production cross section in ultra-peripheral Pb-Pb collisions at the LHC.
This charmonium excited state is reconstructed via the $\psi$(2S) $\rightarrow
l^{+}l^{-}$ and $\psi$(2S) $\rightarrow$ J/$\psi \pi^{+}\pi^{-}$ decays, where
the J/$\psi$ decays into two leptons. The analysis is based on an event sample
corresponding to an integrated luminosity of about 22 $\mu\rm{b}^{-1}$. The
cross section for coherent $\psi$(2S) production in the rapidity interval
$-0.9<y<0.9$ is $\mathrm{d}\sigma_{\psi{\rm(2S)}}^{\rm coh}/\mathrm{d}y
=0.83\pm 0.19\big(\mathrm{\rm{stat}+{\rm syst}}\big)$ mb. The $\psi$(2S) to
J/$\psi$ coherent cross section ratio is $0.34^{+0.08}_{-0.07}(\rm{stat}+{\rm
syst})$. The obtained results are compared to predictions from theoretical
models.

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The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
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The categories of this paper are: stat
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The categories of this paper are: nlin
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The categories of this paper are: mtrl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: astro-ph
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph