  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.
