Kerr-(Anti-)De Sitter Black Holes As Particle Accelerators

In2009, M. Banados, J. Silk and S. M. West (BSW) proved that Kerr black holes could act as particle accelerators with arbitrarily high center-of-mass energy, if the 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. So we may expect that the Kerr-(anti-) de Sitter black hole could be a probe of Planck-scale physics or even higher energy scale physics.