Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Monopolium: the key to monopoles   Dirac showed that the existence of one magnetic pole in the universe could
offer an explanation for the discrete nature of the electric charge. Magnetic
poles appear naturally in most Grand Unified Theories. Their discovery would be
of greatest importance for particle physics and cosmology. The intense
experimental search carried thus far has not met with success. Moreover, if the
monopoles are very massive their production is outside the range of present day
facilities. A way out of this impasse would be if the monopoles bind to form
monopolium, a monopole- antimonopole bound state, which is so strongly bound,
that it has a relatively small mass. Under these circumstances it could be
produced with present day facilities and the existence of monopoles could be
indirectly proven. We study the feasibility of detecting monopolium in present
and future accelerators.

8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int