Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Closing in on the Primordial Abundance of Deuterium   We present our measurements of the deuterium to hydrogen ratio (D/H) in QSO
absorption systems, which give D/H = 3.40 $\pm 0.25 \times 10^{-5}$ based on
analysis of four independent systems. We discuss the properties of two systems
which provide the strongest constraints on D/H. We outline the systematic
effects involved in measurements of D/H and introduce a sophisticated method of
analysis which properly accounts for these effects.

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The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
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The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an