Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Clustering, GUT scale and neutrino masses in Ultrahigh energy cosmic
  rays
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
19
The categories of this paper are: eess