Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The investigation of spin effects in photon production with fermion pair
  in gamma-gamma collisions   The exclusive reaction $ \gamma\gamma\to f \bar{f} \gamma$ is considered as
the possible calibration process on the linear photon collider. We analyse the
energy spectrum and total cross section dependence on the detector parameters
at various initial beam helicities.

20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg