Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An improved half-life limit of the double beta decay of $^{94}$Zr into
  the excited state of $^{94}$Mo   A search for the double beta decay transition of $^{94}$Zr into the first
excited state of $^{94}$Mo has been performed at the Felsenkeller underground
laboratory in Dresden, Germany. A 341.1 g zirconium sample with natural
isotopic composition has been measured for 43.9 d in an ultra low background
gamma spectroscopy setup. No signal has been observed and a new best lower
half-life limit is set as $5.2\times10^{19}$ yr (90% CI). This limit is valid
for the $0\nu\beta\beta$ and $2\nu\beta\beta$ decay into excited states of
$^{94}$Mo but cannot distinguish between the two modes. Existing limits are
improved by 50%.

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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
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The categories of this paper are: math-ph
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
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The categories of this paper are: chem-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol