Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of Ultra-High Energy Cosmic Ray Composition Using Telescope
  Array's Middle Drum Detector and Surface Array in Hybrid Mode   Previous measurements of the composition of Ultra-High Energy Cosmic
Rays(UHECRs) made by the High Resolution Fly's Eye(HiRes) and Pierre Auger
Observatory(PAO) are seemingly contradictory, but utilize different detection
methods, as HiRes was a stereo detector and PAO is a hybrid detector. The five
year Telescope Array(TA) Middle Drum hybrid composition measurement is similar
in some, but not all, respects in methodology to PAO, and good agreement is
evident between data and a light, largely protonic, composition when comparing
the measurements to predictions obtained with the QGSJetII-03 and QGSJet-01c
models. These models are also in agreement with previous HiRes stereo
measurements, confirming the equivalence of the stereo and hybrid methods. The
data is incompatible with a pure iron composition, for all models examined,
over the available range of energies. The elongation rate and mean values of
Xmax are in good agreement with Pierre Auger Observatory data. This analysis is
presented using two methods: data cuts using simple geometrical variables and a
new pattern recognition technique.

15
The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex
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The categories of this paper are: econ
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: q-fin
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The categories of this paper are: nlin
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The categories of this paper are: cmp-lg
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The categories of this paper are: cond-mat
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The categories of this paper are: chao-dyn