Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measurement of the cosmic ray antiproton/proton flux ratio at TeV
  energies with the ARGO-YBJ detector   Cosmic ray antiprotons provide an important probe to study the cosmic ray
propagation in the interstellar space and to investigate the existence of dark
matter. Acting the Earth-Moon system as a magnetic spectrometer, paths of
primary antiprotons are deflected in the opposite sense with respect to those
of the protons in their way to the Earth. This effect allows, in principle, the
search for antiparticles in the direction opposite to the observed deficit of
cosmic rays due to the Moon (the so-called `Moon shadow').
  The ARGO-YBJ experiment, located at the Yangbajing Cosmic Ray Laboratory
(Tibet, P.R. China, 4300 m a.s.l., 606 g/cm$^2$), is particularly effective in
measuring the cosmic ray antimatter content via the observation of the cosmic
rays shadowing effect due to: (1) good angular resolution, pointing accuracy
and long-term stability; (2) low energy threshold; (3) real sensitivity to the
geomagnetic field.
  Based on all the data recorded during the period from July 2006 through
November 2009 and on a full Monte Carlo simulation, we searched for the
existence of the shadow cast by antiprotons in the TeV energy region. No
evidence of the existence of antiprotons is found in this energy region. Upper
limits to the $\bar{p}/p$ flux ratio are set to 5 % at a median energy of 1.4
TeV and 6 % at 5 TeV with a confidence level of 90%. In the TeV energy range
these limits are the lowest available.

37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg