# Kerr-de Sitter and Kerr-anti-de Sitter black holes as accelerators for spinning particles

## TL;DR

This paper investigates how Kerr-(anti-)de Sitter black holes can serve as natural particle accelerators, revealing that the cosmological constant influences the conditions under which arbitrarily high-energy collisions occur.

## Contribution

It extends previous Kerr black hole acceleration studies to include cosmological constants, showing non-extremal Kerr-de Sitter black holes can also achieve infinite collision energies.

## Key findings

- Kerr-anti-de Sitter black holes require extremality for infinite energy collisions.
- Kerr-de Sitter black holes can have divergent collision energy even if non-extremal.
- Cosmological constant significantly affects the acceleration capabilities of black holes.

## Abstract

It is shown that the Kerr black hole could act as accelerators for spinning particles. In principle, it could obtain arbitrarily high energy for extremal Kerr black hole. In this paper, we extend the previous research to the Kerr-(anti-)de Sitter background and find that the cosmological constant plays an important role in the result. For the case of Kerr-anti-de Sitter black holes, like the Kerr background, only the extremal Kerr-anti-de Sitter black holes can have a divergent center-of-mass energy of collision. While, for the case of Kerr-de Sitter black holes, the collision of two spinning particles can take place on the outer horizon of the black holes and the center-of-mass energy of collision can blow up if one of the collision particle takes the critical angular momentum. Hence, non-extremal Kerr-de Sitter black holes could also act as accelerators with arbitrarily high center-of-mass energy for spinning particles.