Particle acceleration in Kerr–(anti-)de Sitter black hole backgrounds

Abstract

Banãdos, Silk and West (BSW) proved that Kerr black holes could act as particle accelerators with arbitrarily high center-of-mass energy, if two conditions are satisfied: (1) these black holes are extremal; (2) one of the colliding particles has critical angular momentum. In this paper, we extend the research to the cases of Kerr–(anti-)de Sitter black holes and find that the cosmological constant has an important effect on the result. In order for the case of Kerr–anti-de Sitter black holes (with negative cosmological constant) to get arbitrary high center-of-mass energy, we need an additional condition besides the above two for Kerr ones. While, for the case of general Kerr–de Sitter black holes (with positive cosmological constant), the collision of two particles can take place on the outer horizon of the black holes and the center-of-mass energy of collision can blow up arbitrarily if the above second condition is satisfied. Hence, non-extremal Kerr-de Sitter black holes could also act as particle accelerators with arbitrarily high center-of-mass energy.