Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: W, Z and photon production in CMS   The production of electroweak bosons (photons, W and Z particles) in PbPb and
pp collisions at sqrt(s) = 2.76 TeV per interacting nucleon pair has been
measured with the CMS detector at the LHC. Direct photon production is studied
using samples of isolated photons. W and Z bosons are reconstructed through
their leptonic decay into muons. Their production rate in PbPb data is studied
as a function of the centrality of the collision and compared to that in pp
interactions, once normalized by the number of binary nucleon-nucleon
interactions. The results are also compared to next-to-leading-order
perturbative QCD calculations.

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The categories of this paper are: econ
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The categories of this paper are: astro-ph
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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: nucl-th
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The categories of this paper are: math-ph
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The categories of this paper are: eess
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: cs
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci