Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kerr black holes as accelerators of spinning test particles   It has been shown that ultraenergetic collisions can occur near the horizon
of an extremal Kerr black hole. Previous studies mainly focused on geodesic
motions of particles. In this paper, we consider spinning test particles whose
orbits are non-geodesic. By employing the Mathisson-Papapetrou-Dixon equation,
we find the critical angular momentum satisfies $J=2E$ for extremal Kerr black
holes. Although the conserved angular momentum $J$ and energy $E$ have been
redefined in the presence of spin, the critical condition remains the same
form. If a particle with this angular momentum collides with another particle
arbitrarily close to the horizon of the black hole, the center-of-mass energy
can be arbitrarily high. We also prove that arbitrarily high energies cannot be
obtained for spinning particles near the horizons of non-extremal Kerr black
holes.

23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph