Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Spectator Electromagnetic Effect on Charged Pion Spectra in
  Peripheral Ultrarelativistic Heavy-Ion Collisions   We estimate the electromagnetic effect of the spectator charge on the
momentum spectra of $\pi^+$ and $\pi^-$ produced in peripheral Pb+Pb collisions
at SPS energies. We find that the effect is large and results in strongly
varying structures in the $x_F$ dependence of the $\pi^+/\pi^-$ ratio,
especially at low transverse momenta where a deep valley in the above ratio is
predicted at $x_F \sim$ 0.15 -- 0.20.
  It appears that the effect depends on initial conditions. Thus, it provides
new information on the space and time evolution of the non-perturbative pion
creation process.

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The categories of this paper are: q-alg
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
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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: alg-geom
4
The categories of this paper are: cond-mat
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: hep-lat