Collision of spinning particles near BTZ black holes

TL;DR

This paper investigates the collision energies of spinning particles near BTZ black holes, revealing conditions under which infinite energy collisions can occur and constraints on particle angular momentum.

Contribution

It demonstrates that particles with critical angular momentum cannot exist outside the horizon, but near-extremal black holes allow high-energy collisions with subcritical particles.

Findings

Divergence of collision energy at critical angular momentum

Critical particles cannot exist outside the horizon

High-energy collisions possible near extremal black holes

Abstract

We study the collision property of spinning particles near a Ba\~nados-Teitelboim-Zanelli (BTZ) black hole. Our results show that although the center-of-mass energy of two ingoing particles diverges if one of the particles possesses a critical angular momentum, however, particle with critical angular momentum can not exist outside of the horizon due to the violation of timelike constraint. Further detailed investigation indicates that only the particle with a subcritical angular momentum is allowed to exist near an extremal rotating BTZ black hole and the corresponding collision center-of-mass energy can be arbitrarily large in a critical angular momentum limit.