Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Momentum Dependence of the Pion Cloud for Rho Mesons in Nuclear Matter   We extend hadronic models for rho-meson propagation in cold nuclear matter
via coupling to in-medium pions to include finite three-momentum. Special care
is taken to preserve gauge invariance. Consequences for photoabsorption on the
proton and on nuclei as well as for the dilepton production in relativistic
heavy-ion collisions are discussed.

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The categories of this paper are: q-bio
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The categories of this paper are: supr-con
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The categories of this paper are: eess
24
The categories of this paper are: dg-ga
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The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: astro-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas