Kerr black holes as accelerators of spinning test particles

Understand

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.