Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Is DAMA Bathing in a Sea of Radioactive Argon?   A hypothesis is proposed to explain the long-standing DAMA/LIBRA puzzle.
Introduced into the DAMA/LIBRA shielding is a purge gas of nominally
high-purity nitrogen, which under this hypothesis contains argon impurities.
Argon is introduced into the nitrogen purge gas either through leaks in the
purge gas plumbing, or through commercially-supplied bottled nitrogen, diffuses
through materials in the detector housings, and then comes in direct contact
with the DAMA/LIBRA detectors. These argon impurities can then lead to a
modulating 2.8 keV background under two scenarios. Scenario 1): These
impurities include the isotope 37Ar, which decays by electron capture, emitting
a 2.8 keV x-ray. These decays appear as single-site, monoenergetic events in
DAMA/LIBRA, and produce an annual modulation due to the variation of neutron
flux in the atmosphere and at the Earth's surface, which in turn leads to a
seasonal variation in 37Ar production from the reactions
$^{40}\textrm{Ca}(\textrm{n,}\alpha)^{37}\textrm{Ar}$ and
$^{36}\textrm{Ar}(\textrm{n,}\gamma)^{37}\textrm{Ar}$. Scenario 2): Radon is
also in the DAMA/LIBRA purge gas, modulating seasonally at a rate below the
current DAMA/LIBRA limits. When radon or its short-lived daughters decay, the
resulting beta, gamma, and bremsstrahlung radiation cause stable 40Ar to be
ionized within the copper housings surrounding the NaI(Tl) detectors, resulting
in characteristic 2.8 keV x-rays. Modulating backgrounds might also result from
radon-induced neutron or gamma-ray flux from the surrounding cavern, leading to
a small modulating background enhanced at low energy by the presence of 40Ar
within the copper housings. These two scenarios are straightforward to test
through assay of the purge gas as well as Monte Carlo and laboratory study of
the DAMA/LIBRA copper housings when excited by ionizing radiation.

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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-lat
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: q-bio
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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: ao-sci
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ph