Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Atmospheric Muon Charge Ratio at the MINOS Near Detector   The magnetized MINOS near detector can accurately determine the charge sign
of atmospheric muons, this facilitates a measurement of the atmospheric muon
charge ratio. To reduce the systematic error associated with geometric bias and
acceptance we have combined equal periods of data obtained with opposite
magnetic field polarities. We report a charge ratio of
$1.2666\pm0.0015(stat.)^{+0.0096}_{-0.0088}(syst.)$ at a mean
E$_{\mu,0}cos(\theta)$=\unit[63]{GeV}. This measurement is consistent with the
world average\cite{Hebbeker}\cite{Haino}\cite{Achard} but significantly lower
than the earlier observation at the MINOS far detector\cite{Adamson}. This
increase is shown to be consistent with the hypothesis that a greater fraction
of the observed muons arise from kaon decay within the cosmic ray shower.

9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin