Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Possible Trajectories of Particles with Spin. II. Particles in
  the Stationary Homogeneous Magnetic Field   The behavior of spinning particles in the stationary homogeneous magnetic
field is considered and all types of trajectories for massive and massless
particles are found. It is shown that spin of particles in a magnetic field is
always arranged parallel or antiparallel to the field. Helicity $e$ plays a
role of electric charge. The oscillation frequency of massless particle in a
magnetic field increases.

11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an