Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Search for Single Top Production in e+e- Collisions at sqrt(s) up to
  209GeV   Single top production via the flavour changing neutral current reactions e+e-
-> \bar{t}c, \bar{t}u is searched for within the 214 pb-1 of data collected by
ALEPH at centre-of-mass energies between 204 and 209 GeV. No deviation from the
Standard Model expectation is observed and upper limits on the single top
production cross sections are derived. The combination with data collected at
lower centre-of-mass energies yields an upper limit on the branching ratio BR(t
-> Zc)+BR(t -> Zu) 14%, for BR(t -> \gamma c)+BR(t -> \gamma u)= 0 and mt=174
GeV/c2.

31
The categories of this paper are: ao-sci
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The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg