Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Quasimonoenergetic electron beams produced by colliding cross-polarized
  laser pulses in underdense plasmas
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex