Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Limits on the TeV flux of diffuse gamma rays as measured with the HEGRA
  air shower array   Using data from the HEGRA air shower array, taken in the period from April
1998 to March 2000, upper limits on the ratio I_gamma /I_CR of the diffuse
photon flux I_gamma to the hadronic cosmic ray flux I_CR are determined for the
energy region 20 TeV to 100 TeV. The analysis uses a gamma-hadron
discrimination which is based on differences in the development of photon- and
hadron-induced air showers after the shower maximum. A method which is
sensitive only to the non-isotropic component of the diffuse photon flux yields
an upper limit of I_gamma /I_CR (at 54 TeV) < 2.0*10^-3 (at the 90% confidence
level) for a sky region near the inner galaxy (20 degrees < galactic longitude
<60 degrees and |galactic latitude|<5 degrees). A method which is sensitive to
both the isotropic and the non-isotropic component yields global upper limits
of I_gamma /I_CR (at 31 TeV) <1.2*10^-2 and I_gamma /I_CR (at 53 TeV) <
1.4*10^-2 (at the 90% confidence level).

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The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th