Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stable quark matter in cosmic rays?   Stable lumps of quark matter may be present in cosmic rays at a flux level,
which can be detected by high precision cosmic ray experiments sensitive to
anomalous "nuclei" with high mass-to-charge ratio. The properties of these
lumps, called strangelets, are described, and so is the production and
propagation of strangelets in cosmic rays. Two experiments underway which are
sensitive to a strangelet flux in the predicted range are briefly described.
Finally it is summarized how strangelets circumvent the acceleration problem
encountered by conventional candidates for ultra-high energy cosmic rays and
move the Greisen-Zatsepin-Kuzmin cutoff to energies well above the observed
maximum energies.

19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga