Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Neutrino cross sections at high energies and the future observations of
  ultrahigh-energy cosmic rays   We show that future detectors of ultrahigh-energy cosmic-ray neutrinos will
be able to measure neutrino-nucleon cross section at energies as high as
10^{11}GeV or higher. We find that the flux of up-going charged leptons per
unit surface area produced by neutrino interactions below the surface is
inversely proportional to the cross section. This contrasts with the rate of
horizontal air showers (HAS) due to neutrino interactions in the atmosphere,
which is proportional to the cross section. Thus, by comparing the HAS and
up-going air shower (UAS) rates, the neutrino-nucleon cross section can be
inferred. Taken together, up-going and horizontal rates ensure a healthy total
event rate, regardless of the value of the cross section.

20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph