Unbounded Energy Collisions inside and outside Black Holes

Abstract

The possibility of on-horizon collisions of unbounded energy in the case of an extreme Kerr black hole is known as the BSW effect. It is also a widely accepted point of view that the energy collision of two identical particles of mass m near the horizon of a Schwarzschild black hole is limited to a value of 25 m. We show that there are two possible scenarios for unbounded energy collisions both for the exterior and for the interior of spherically symmetric black holes. Similar scenarios are found for axially symmetric black holes. It is shown that divergent (infinite) energy on-(inner)horizon collisions are excluded due to the anisotropic character of the dynamics of black hole interiors.