Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Targeted Search for Point Sources of EeV Neutrons   A flux of neutrons from an astrophysical source in the Galaxy can be detected
in the Pierre Auger Observatory as an excess of cosmic-ray air showers arriving
from the direction of the source. To avoid the statistical penalty for making
many trials, classes of objects are tested in combinations as nine "target
sets", in addition to the search for a neutron flux from the Galactic Center or
from the Galactic Plane. Within a target set, each candidate source is weighted
in proportion to its electromagnetic flux, its exposure to the Auger
Observatory, and its flux attenuation factor due to neutron decay. These
searches do not find evidence for a neutron flux from any class of candidate
sources. Tabulated results give the combined p-value for each class, with and
without the weights, and also the flux upper limit for the most significant
candidate source within each class. These limits on fluxes of neutrons
significantly constrain models of EeV proton emission from non-transient
discrete sources in the Galaxy.

2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin