A probe particle in a Kerr-Newman-de Sitter cosmos

We consider the force acting on a spinning charged test particle (probe par ticle) with mass m and charge q in a slowly rotating Kerr-Newman-de Sitter (KNdS) black hole with mass M and charge Q. We consider the case in which t he spin vector of the probe particle is parallel to the angular momentum ve ctor of the KNdS spacetime. We take account of the gravitational spin-spin interaction under the slow rotation limit of the KNdS spacetime. When Q = M and q = m, we show that the force balance holds including the spin-spin in teraction and the motion is approximately the same as that of a particle in de Sitter spacetime. This force cancellation suggests the possibility of t he existence of an exact solution of a spinning multi-KNdS black hole.