Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: MuLan Measurement of the Positive Muon Lifetime and Determination of the
  Fermi Constant   We report results from the MuLan measurement of the positive muon lifetime.
The experiment was conducted at the Paul Scherrer Institute using a
time-structured surface muon beam and a segmented plastic scintillator array.
Two different in-vacuum muon stopping targets were used: a ferromagnetic foil
with a large internal magnetic field and a quartz crystal in a moderate
external magnetic field. From a total of 1.6 x 10^{12} decays, we obtained the
muon lifetime tau_mu = 2196980.3(2.2) ps (1.0 ppm) and Fermi constant G_F =
1.1663787(6) x 10^{-5} GeV^{-2} (0.5 ppm).

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The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
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The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: hep-lat
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn