Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmological Deuterium Abundance and the Baryon Density of the Universe   Standard big bang nucleosynthesis (BBNS) promises accurate predictions of the
primordial abundances of deuterium, helium-3, helium-4 and lithium-7 as a
function of a single parameter. Previous measurements have nearly always been
interpreted as confirmation of the model (Copi, Schramm & Turner 1995). Here we
present a measurement of the deuterium to hydrogen ratio (D/H) in a newly
discovered high redshift metal-poor gas cloud at redshift $z=2.504$. This
confirms our earlier measurement of D/H (Tytler, Fan & Burles 1996), and
together they give the first accurate measurement of the primordial D
abundance, and a ten fold improvement in the accuracy of the cosmological
density of ordinary matter.This is a high density, with most ordinary matter
unaccounted or dark, which is too high to agree with measurements of the
primordial abundances of helium-4 and lithium-7. Since the D/H measurement is
apparently simple, direct, accurate and highly sensitive, we propose that
helium requires a systematic correction, and that population II stars have less
than the primordial abundance of $^7$Li. Alternatively, there is no concordance
between the light element abundances, and the simple model of the big bang must
be incomplete and lacking physics, or wrong.

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The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
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The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
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The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas