Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Axions 05   The Strong CP Problem and its resolution through the existence of an axion
are briefly reviewed. The combined constraints from accelerator searches, the
evolution of red giants and the duration of the SN 1987a neutrino pulse require
the axion mass $m_a$ to be less than $3 \cdot 10^{-3}$ eV. On the other hand,
the requirement that the axion does not overclose the universe implies a lower
bound on $m_a$ of order $10^{-6}$ eV. This lower bound can, however, be relaxed
in a number of ways. If $m_a$ is near the lower bound, axions are an important
contribution to the energy density of the universe in the form of (very) cold
dark matter. Dark matter axions can be searched for on Earth by stimulating
their conversion to microwave photons in an electromagnetic cavity permeated by
a magnetic field. Using this technique, limits on the local halo density have
been placed by the Axion Dark Matter eXperiment. I'll give a status report on
ADMX and its upgrade presently under construction. I'll also report on recent
results from solar axion searches and laser experiments.

12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
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The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
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The categories of this paper are: econ
28
The categories of this paper are: alg-geom
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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: stat
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org