Charged Spinning Black Holes as Particle Accelerators

Understand

It has recently been pointed out that the spinning Kerr black hole with maximal spin could act as a particle collider with arbitrarily high center-of-mass energy.

• In this paper, we will extend the result to the charged spinning black hole, the Kerr-Newman black hole.
• The center-of-mass energy of collision for two uncharged particles falling freely from rest at infinity depends not only on the spin $a$ but also on the charge $Q$ of the black hole.
• We find that an unlimited center-of-mass energy can be approached with the conditions: (1) the collision takes place at the horizon of an extremal black hole; (2) one of the colliding particles has critical angular momentum; (3) the spin $a$ of the extremal black hole satisfies $\frac{1}{\sqrt{3}}\leq \frac{a}{M}\leq 1$, where $M$ is the mass of the Kerr-Newman black hole.