Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Positronium-ion decay   We present a precise theoretical prediction for the decay width of the bound
state of two electrons and a positron (a negative positronium ion), Gamma(Ps^-)
= 2.087 085(12)/ns. We include O(alpha^2) effects of hard virtual photons as
well as soft corrections to the wave function and the decay amplitude. An
outcome of a large-scale variational calculation, this is the first result for
second-order corrections to a decay of a three-particle bound state. It will be
tested experimentally in the new positronium-ion facility in Garching in
Germany.

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The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: comp-gas
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The categories of this paper are: quant-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: atom-ph
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn