Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of Radiative Decays of Psi(2S) Mesons   We studied the decay psi(2S) to gamma eta_c(2S) with 25.9 million psi(2S)
events collected with the CLEO-c detector. No psi(2S) to gamma eta_c(2S) decays
were observed in any of the eleven exclusive eta_c(2S) decay modes studied. The
product branching fraction upper limits were determined for all modes. The 90%
confidence level upper limit of branching fraction of psi(2S) to gamma eta_c
(2S) was obtained.

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The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: econ
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: physics
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-bio
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The categories of this paper are: hep-th
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The categories of this paper are: chem-ph