Unbound geodesics from the ergosphere and potential observability of
  debris from ultrahigh energy particle collisions
  Particle collisions in black hole ergoregions may result in extremely high
center of mass energies that could probe new physics if escape to infinity were
possible. Here we show that some geodesics at high inclinations to the
equatorial plane may be unbound. Hence a finite flux of annihilation debris is
able to escape, especially in the case of near-extremal Kerr black holes and if
the Penrose process plays a role. For a class of Penrose processes, we show
that the Wald inequalities are satisfied, allowing the Penrose process to have
a key role in high energy ejection. Hence the possibility of observing new
physics effects from a black hole accelerator at unprecedentedly high particle
collision energies remains a tantalizing, if futuristic, experimental vision.
